fluoxetine/olanzapine (Rx)

Depression Associated with Bipolar I Disorder

Indicated for acute depressive episodes in bipolar I disorder

Initial: 25 mg/6 mg PO qDay in evening

If needed, may titrate with 25-50 mg fluoxetine/6-12 mg olanzapine; not to exceed 75 mg/18 mg per day

Treatment of Resistant Depression

Indicated for treatment resistant depression (ie, major depressive disorder in patients who do not respond to 2 separate trials of different antidepressants of adequate dose and duration in the current episode)

Initial: 25 mg/6 mg PO qDay in evening

If needed, may titrate with 25-50 mg fluoxetine/6-12 mg olanzapine; not to exceed 75 mg/18 mg per day

Dosage Modifications

Hypotensive diathesis, hepatic impairment, or slow metabolism: Initiate with 25 mg/3 mg to 25 mg/6 mg PO qDay

Slow metabolism observed in females, elderly, and nonsmokers

Discontinue gradually

Coadministration with other monoamine oxidase inhibitor (MAOI)s (eg, linezolid or methylene blue)

• Do not start fluoxetine/olanzapine in patients treated with linezolid or IV methylene blue due to the increased risk of serotonin syndrome
• If alternatives to linezolid or IV methylene blue treatment are not available and potential benefits of linezolid or intravenous methylene blue are judged to outweigh risks of serotonin syndrome, promptly stop fluoxetine/olanzapine, and linezolid or intravenous methylene blue can be administered
• Monitor for symptoms of serotonin syndrome for 5 weeks or until 24 hr after the last dose of linezolid or IV methylene blue, whichever comes first; resume 24 hr after the last dose of linezolid or IV methylene blue

Dosing Considerations

Switching to or from a MAOIs to treat psychiatric disorders

• Allow at least 14 days to elapse prior to starting fluoxetine/olanzapine after discontinuation of an MAOI intended to treat psychiatric disorders
• Conversely, allow at least 5 weeks after stopping fluoxetine/olanzapine before starting an MAOI intended to treat psychiatric disorders

Depression Associated with Bipolar I Disorder

Indicated for acute depressive episodes in bipolar I disorder in children and adolescents aged 10-17 years

<10 years: Safety and efficacy not established

10-17 years

• Initial: 25 mg/3 mg PO qDay in evening
• If needed, may titrate with 25-50 mg fluoxetine/6-12 mg olanzapine; not to exceed 50 mg/12 mg per day

Clinical studies of fluoxetine/olanzapine did not include sufficient numbers of patients ≥65 year; use with caution

Initiate with 25 mg/3 mg to 25 mg/6 mg PO qDay

Contraindicated (7)

• amisulpride

  amisulpride, olanzapine. Either increases toxicity of the other by Other (see comment). Contraindicated. Comment: Increases risk of neuroleptic malignant syndromeIncreases risk of neuroleptic malignant syndrome.

• artemether/lumefantrine

  artemether/lumefantrine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.

• dronedarone

  olanzapine and dronedarone both increase QTc interval. Contraindicated.

• eliglustat

  fluoxetine increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.

• fezolinetant

  fluoxetine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors
  
  olanzapine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

• goserelin

  goserelin increases toxicity of fluoxetine by QTc interval. Contraindicated. Increases risk of torsades de pointes.

• thioridazine

  olanzapine and thioridazine both increase QTc interval. Contraindicated.

Serious - Use Alternative (197)

• abametapir

  abametapir will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP1A2 substrates. If not feasible, avoid use of abametapir.

• adagrasib

  adagrasib, olanzapine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.
  
  adagrasib, fluoxetine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.

• alfentanil

  alfentanil, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• amiodarone

  olanzapine and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.

• amiodarone

  amiodarone and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• amisulpride

  amisulpride and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  amisulpride and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.

• amitriptyline

  fluoxetine will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug.

• anagrelide

  olanzapine and anagrelide both increase QTc interval. Avoid or Use Alternate Drug.

• amoxapine

  fluoxetine and amoxapine both increase serotonin levels. Avoid or Use Alternate Drug.

• anagrelide

  anagrelide and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• apomorphine

  olanzapine decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.
  
  apomorphine and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• aripiprazole

  fluoxetine will increase the level or effect of aripiprazole by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  aripiprazole and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• arsenic trioxide

  arsenic trioxide and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and arsenic trioxide both increase QTc interval. Avoid or Use Alternate Drug.

• artemether

  artemether and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  artemether and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• artemether/lumefantrine

  olanzapine and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

• atomoxetine

  atomoxetine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine

  olanzapine and asenapine both increase QTc interval. Avoid or Use Alternate Drug.

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• bromocriptine

  olanzapine decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• buprenorphine

  olanzapine and buprenorphine both increase QTc interval. Avoid or Use Alternate Drug. If concurrent use of olanzapine and buprenorphine is necessary, consider dose reduction of one or both drugs.
  
  buprenorphine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine buccal

  buprenorphine buccal and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine buccal and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• buprenorphine subdermal implant

  buprenorphine subdermal implant and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine subdermal implant and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• buprenorphine transdermal

  buprenorphine transdermal and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine transdermal and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• buprenorphine, long-acting injection

  buprenorphine, long-acting injection and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine, long-acting injection and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• bupropion

  fluoxetine increases toxicity of bupropion by unspecified interaction mechanism. Avoid or Use Alternate Drug. May lower seizure threshold; keep bupropion dose as low as possible.

• cabergoline

  olanzapine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

• buspirone

  fluoxetine and buspirone both increase serotonin levels. Avoid or Use Alternate Drug.

• calcium/magnesium/potassium/sodium oxybates

  olanzapine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• carvedilol

  fluoxetine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• ceritinib

  ceritinib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  ceritinib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• chlorpromazine

  olanzapine and chlorpromazine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• cimetidine

  fluoxetine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• ciprofloxacin

  olanzapine and ciprofloxacin both increase QTc interval. Avoid or Use Alternate Drug.

• citalopram

  citalopram and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  citalopram and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

• clarithromycin

  clarithromycin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• clomipramine

  fluoxetine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and clomipramine both increase serotonin levels. Avoid or Use Alternate Drug.

• clopidogrel

  fluoxetine decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .

• clozapine

  clozapine and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• crizotinib

  crizotinib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• cyclobenzaprine

  fluoxetine and cyclobenzaprine both increase serotonin levels. Avoid or Use Alternate Drug.

• dacomitinib

  dacomitinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.

• degarelix

  degarelix and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• desflurane

  desflurane and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  desflurane and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• desipramine

  fluoxetine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and desipramine both increase serotonin levels. Avoid or Use Alternate Drug.

• disopyramide

  olanzapine and disopyramide both increase QTc interval. Avoid or Use Alternate Drug.

• desvenlafaxine

  fluoxetine and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.

• dextromethorphan

  fluoxetine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

• disopyramide

  disopyramide and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• dolasetron

  dolasetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• dopamine

  olanzapine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

• dosulepin

  fluoxetine and dosulepin both increase serotonin levels. Avoid or Use Alternate Drug.

• doxepin

  fluoxetine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and doxepin both increase serotonin levels. Avoid or Use Alternate Drug.

• droperidol

  olanzapine and droperidol both increase QTc interval. Avoid or Use Alternate Drug.

• duloxetine

  fluoxetine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  duloxetine and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug.

• eliglustat

  eliglustat and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and eliglustat both increase QTc interval. Avoid or Use Alternate Drug.

• encorafenib

  encorafenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Encorafenib is associated with dose-dependent QTc interval prolongation. Avoid with drugs known to prolong QT interval.
  
  encorafenib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• entrectinib

  fluoxetine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.

• erdafitinib

  olanzapine will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

• escitalopram

  fluoxetine will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  escitalopram and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug.

• eribulin

  eribulin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• erythromycin base

  olanzapine and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  olanzapine and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  olanzapine and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin stearate

  olanzapine and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.

• fedratinib

  olanzapine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
  
  fluoxetine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

• fentanyl

  fentanyl, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fexinidazole

  fexinidazole and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.

• fentanyl intranasal

  fentanyl intranasal, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fentanyl transdermal

  fentanyl transdermal, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fentanyl transmucosal

  fentanyl transmucosal, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fexinidazole

  fexinidazole and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.

• flecainide

  fluoxetine will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• fluphenazine

  fluoxetine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluphenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• fluvoxamine

  fluvoxamine and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  olanzapine and fluvoxamine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluvoxamine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

• foscarnet

  olanzapine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

• gilteritinib

  gilteritinib will decrease the level or effect of fluoxetine by Other (see comment). Avoid or Use Alternate Drug. Coadministration of gilteritinib with drugs that inhibit 5HT2B or sigma nonspecific receptors. Avoid use of these drugs with gilteritinib unless coadministration is necessary.
  
  gilteritinib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• givosiran

  givosiran will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP1A2 substrates with givosiran. If unavoidable, decrease the CYP1A2 substrate dosage in accordance with approved product labeling.
  
  givosiran will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.

• glasdegib

  olanzapine and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.
  
  fluoxetine and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.

• goserelin

  olanzapine and goserelin both increase QTc interval. Avoid or Use Alternate Drug.

• granisetron

  granisetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• haloperidol

  fluoxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  haloperidol will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• histrelin

  olanzapine and histrelin both increase QTc interval. Avoid or Use Alternate Drug.
  
  histrelin increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• hydrocodone

  hydrocodone, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• hydromorphone

  fluoxetine will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  hydromorphone, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• hydroxychloroquine sulfate

  hydroxychloroquine sulfate and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  hydroxychloroquine sulfate and olanzapine both increase QTc interval. Avoid or Use Alternate Drug.

• hydroxyzine

  hydroxyzine increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• ibutilide

  olanzapine and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.

• ibutilide

  fluoxetine and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.

• iloperidone

  fluoxetine will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  olanzapine and iloperidone both increase QTc interval. Avoid or Use Alternate Drug.

• imipramine

  fluoxetine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and imipramine both increase serotonin levels. Avoid or Use Alternate Drug.

• inotuzumab

  olanzapine and inotuzumab both increase QTc interval. Avoid or Use Alternate Drug.

• indapamide

  fluoxetine and indapamide both increase QTc interval. Avoid or Use Alternate Drug.

• isoflurane

  isoflurane and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  isoflurane and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• ivosidenib

  ivosidenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.
  
  ivosidenib will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2C9 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.
  
  ivosidenib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.

• lefamulin

  lefamulin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug.
  
  lefamulin and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• leniolisib

  leniolisib will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid leniolisib with CYP1A2 substrates that have a narrow therapeutic index

• levomilnacipran

  fluoxetine and levomilnacipran both increase serotonin levels. Avoid or Use Alternate Drug.

• lenvatinib

  olanzapine and lenvatinib both increase QTc interval. Avoid or Use Alternate Drug.

• leuprolide

  olanzapine and leuprolide both increase QTc interval. Avoid or Use Alternate Drug.

• levodopa

  olanzapine decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• levodopa inhaled

  olanzapine decreases effects of levodopa inhaled by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Atypical (2nd generation) antipsychotics inhibit dopamine D2 receptors in varying degrees (clozapine and quetiapine are lower risk). .

• lisuride

  olanzapine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

• lofepramine

  fluoxetine will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and lofepramine both increase serotonin levels. Avoid or Use Alternate Drug.

• lonafarnib

  fluoxetine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.
  
  olanzapine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

• lopinavir

  olanzapine and lopinavir both increase QTc interval. Avoid or Use Alternate Drug.

• lorcaserin

  fluoxetine and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.

• macimorelin

  macimorelin and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.
  
  macimorelin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.

• maprotiline

  olanzapine and maprotiline both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine and maprotiline both increase serotonin levels. Avoid or Use Alternate Drug.

• mefloquine

  mefloquine increases toxicity of olanzapine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.
  
  mefloquine increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.

• meperidine

  fluoxetine and meperidine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  meperidine, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• methadone

  olanzapine and methadone both increase QTc interval. Avoid or Use Alternate Drug.

• methamphetamine

  fluoxetine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• methyldopa

  olanzapine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

• methylenedioxymethamphetamine

  fluoxetine increases toxicity of methylenedioxymethamphetamine by decreasing elimination. Contraindicated.

• metoclopramide

  metoclopramide and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. Additive effects; increased risk for serotonin syndrome, neuroleptic malignant syndrome, dystonia, or other extrapyramidal reactions

• metoclopramide intranasal

  olanzapine increases toxicity of metoclopramide intranasal by pharmacodynamic synergism. Avoid or Use Alternate Drug. Potential for additive effects, including increased frequency and severity of tardive dyskinesia, other extrapyramidal symptoms, and neuroleptic malignant syndrome.
  
  olanzapine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
  
  fluoxetine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
  
  fluoxetine will increase the level or effect of metoclopramide intranasal by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Concurrent use of metoclopramide intranasal and strong CYP2D6 inhibitors is not recommended since the metoclopramide intranasal dose cannot be adjusted.

• metoprolol

  fluoxetine will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• midostaurin

  olanzapine and midostaurin both increase QTc interval. Avoid or Use Alternate Drug.

• mexiletine

  fluoxetine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• milnacipran

  fluoxetine and milnacipran both increase serotonin levels. Avoid or Use Alternate Drug.

• mirtazapine

  mirtazapine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• mobocertinib

  mobocertinib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.
  
  mobocertinib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.

• morphine

  fluoxetine will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  morphine, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• moxifloxacin

  olanzapine and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.

• nebivolol

  fluoxetine will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• nefazodone

  fluoxetine and nefazodone both increase serotonin levels. Avoid or Use Alternate Drug.

• netupitant/palonosetron

  netupitant/palonosetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• nortriptyline

  fluoxetine will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and nortriptyline both increase serotonin levels. Avoid or Use Alternate Drug.

• olopatadine intranasal

  olanzapine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
  
  fluoxetine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• ondansetron

  fluoxetine and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.
  
  ondansetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.
  
  olanzapine and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.

• oxaliplatin

  oxaliplatin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  olanzapine and oxaliplatin both increase QTc interval. Avoid or Use Alternate Drug.
  
  oxaliplatin and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• oxycodone

  oxycodone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Opioids may enhance the serotonergic effects of SSRIs and increase risk for serotonergic syndrome

• paliperidone

  olanzapine and paliperidone both increase QTc interval. Avoid or Use Alternate Drug.

• oxymorphone

  fluoxetine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• ozanimod

  ozanimod increases toxicity of fluoxetine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.

• palonosetron

  palonosetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• panobinostat

  fluoxetine and panobinostat both increase QTc interval. Avoid or Use Alternate Drug. Panobinostat is known to significantly prolong QT interval. Panobinostat prescribing information states use with drugs known to prolong QTc is not recommended.
  
  olanzapine and panobinostat both increase QTc interval. Avoid or Use Alternate Drug.

• paroxetine

  fluoxetine will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  olanzapine and paroxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine and paroxetine both increase serotonin levels. Avoid or Use Alternate Drug.

• pazopanib

  olanzapine and pazopanib both increase QTc interval. Avoid or Use Alternate Drug.

• pentamidine

  fluoxetine and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.

• pefloxacin

  pefloxacin will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

• pentamidine

  olanzapine and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.

• perphenazine

  fluoxetine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  perphenazine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  perphenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• phentermine

  fluoxetine, phentermine. Either increases toxicity of the other by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of serotonin syndrome.

• pimavanserin

  olanzapine and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.

• pimozide

  olanzapine and pimozide both increase QTc interval. Contraindicated.

• pirfenidone

  fluoxetine will increase the level or effect of pirfenidone by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid; coadministration of pirfenidone and moderate CYP1A2 inhibitors result in moderately increased exposure to pirfenidone; if unable to avoid, decrease dose of moderate CYP1A2 inhibitor

• pitolisant

  olanzapine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.

• ponesimod

  olanzapine and ponesimod both increase QTc interval. Avoid or Use Alternate Drug.

• procainamide

  fluoxetine and procainamide both increase QTc interval. Avoid or Use Alternate Drug.

• pramipexole

  olanzapine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

• procainamide

  olanzapine and procainamide both increase QTc interval. Avoid or Use Alternate Drug.

• promethazine

  fluoxetine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• propafenone

  propafenone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  olanzapine and propafenone both increase QTc interval. Avoid or Use Alternate Drug.
  
  propafenone and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• propranolol

  fluoxetine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• quetiapine

  olanzapine and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• protriptyline

  fluoxetine and protriptyline both increase serotonin levels. Avoid or Use Alternate Drug.

• quinidine

  olanzapine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
  
  quinidine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  quinidine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• ranolazine

  olanzapine and ranolazine both increase QTc interval. Avoid or Use Alternate Drug.

• rasagiline

  rasagiline and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. evere CNS toxicity associated with hyperpyrexia has been reported with the combined treatment of an antidepressant and rasagiline. Avoid combination within 14 days of MAOI use.

• ribociclib

  ribociclib increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug.
  
  ribociclib will increase the level or effect of fluoxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  ribociclib increases toxicity of olanzapine by QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.

• risperidone

  fluoxetine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• ropinirole

  olanzapine decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

• safinamide

  olanzapine decreases effects of safinamide by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Dopamine antagonists may decrease safinamide effects and exacerbate Parkinson disease symptoms.

• saquinavir

  olanzapine and saquinavir both increase QTc interval. Avoid or Use Alternate Drug.

• selegiline transdermal

  selegiline transdermal and fluoxetine both decrease serotonin levels. Avoid or Use Alternate Drug.

• selinexor

  selinexor, fluoxetine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.
  
  selinexor, olanzapine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

• sertraline

  sertraline will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and sertraline both increase serotonin levels. Avoid or Use Alternate Drug.

• sevoflurane

  sevoflurane and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• sevoflurane

  sevoflurane and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• siponimod

  siponimod and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and siponimod both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.

• sodium oxybate

  olanzapine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• St John's Wort

  fluoxetine and St John's Wort both increase serotonin levels. Avoid or Use Alternate Drug.

• sotalol

  fluoxetine and sotalol both increase QTc interval. Avoid or Use Alternate Drug.

• sotalol

  olanzapine and sotalol both increase QTc interval. Avoid or Use Alternate Drug.

• sufentanil SL

  sufentanil SL, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• tedizolid

  tedizolid, fluoxetine. Either increases effects of the other by Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. both increase serotonin levels; increased risk of serotonin syndrome.

• tetrabenazine

  olanzapine and tetrabenazine both increase QTc interval. Avoid or Use Alternate Drug.
  
  tetrabenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• thioridazine

  fluoxetine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• thiothixene

  olanzapine and thiothixene both increase QTc interval. Avoid or Use Alternate Drug.

• timolol

  fluoxetine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• tipranavir

  tipranavir will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• tolterodine

  fluoxetine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• toremifene

  olanzapine and toremifene both increase QTc interval. Avoid or Use Alternate Drug.

• trazodone

  fluoxetine and trazodone both increase serotonin levels. Avoid or Use Alternate Drug.
  
  olanzapine and trazodone both increase QTc interval. Avoid or Use Alternate Drug.

• trimipramine

  fluoxetine and trimipramine both increase serotonin levels. Avoid or Use Alternate Drug.

• triptorelin

  olanzapine and triptorelin both increase QTc interval. Avoid or Use Alternate Drug.

• triptorelin

  triptorelin increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• umeclidinium bromide/vilanterol inhaled

  olanzapine increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

• vandetanib

  olanzapine and vandetanib both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine, vandetanib. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. Avoid coadministration with drugs known to prolong QT interval; if a drug known to prolong QT interval must be used, more frequent ECG monitoring is recommended.

• vemurafenib

  olanzapine and vemurafenib both increase QTc interval. Avoid or Use Alternate Drug.
  
  vemurafenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended.

• venlafaxine

  fluoxetine and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.

• vilanterol/fluticasone furoate inhaled

  olanzapine increases toxicity of vilanterol/fluticasone furoate inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

• vilazodone

  fluoxetine, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .

• voriconazole

  fluoxetine will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• vortioxetine

  fluoxetine, vortioxetine. Either increases effects of the other by serotonin levels. Avoid or Use Alternate Drug.

• ziprasidone

  olanzapine and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.

Monitor Closely (561)

• 5-HTP

  fluoxetine and 5-HTP both increase serotonin levels. Modify Therapy/Monitor Closely.

• abiraterone

  abiraterone increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

• abobotulinumtoxinA

  abobotulinumtoxinA increases effects of olanzapine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

• acarbose

  olanzapine, acarbose. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• aceclofenac

  fluoxetine, aceclofenac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• acemetacin

  fluoxetine, acemetacin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• aclidinium

  aclidinium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  aclidinium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• acrivastine

  acrivastine and olanzapine both increase sedation. Use Caution/Monitor.

• albiglutide

  olanzapine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• albuterol

  albuterol and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  albuterol and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• alfentanil

  alfentanil and olanzapine both increase sedation. Use Caution/Monitor.

• alfuzosin

  alfuzosin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluoxetine and alfuzosin both increase QTc interval. Use Caution/Monitor.

• alfuzosin

  olanzapine and alfuzosin both increase QTc interval. Use Caution/Monitor.
  
  alfuzosin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• almotriptan

  almotriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  almotriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• alosetron

  fluoxetine will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• alprazolam

  alprazolam and olanzapine both increase sedation. Use Caution/Monitor.

• alpelisib

  alpelisib will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• amifampridine

  fluoxetine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amifostine

  amifostine, olanzapine. Either increases effects of the other by anti-hypertensive channel blocking. Use Caution/Monitor. Due to its alpha adrenergic antagonism, atypical antipsychotic agents has the potential to enhance the effect of certain antihypertensive agents. Monitor blood pressure and adjust dose accordingly.

• amiodarone

  amiodarone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• amitriptyline

  olanzapine and amitriptyline both increase QTc interval. Use Caution/Monitor.
  
  amitriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and amitriptyline both increase sedation. Use Caution/Monitor.

• amobarbital

  amobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  amobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• amoxapine

  amoxapine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• amoxapine

  olanzapine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and amoxapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and amoxapine both increase QTc interval. Use Caution/Monitor.

• anticholinergic/sedative combos

  anticholinergic/sedative combos decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  anticholinergic/sedative combos decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• apalutamide

  apalutamide will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Coadministration of apalutamide, a weak CYP2C9 inducer, with drugs that are CYP2C9 substrates can result in lower exposure to these medications. Evaluate for loss of therapeutic effect if medication must be coadministered.

• apixaban

  fluoxetine increases effects of apixaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• apomorphine

  apomorphine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and apomorphine both increase sedation. Use Caution/Monitor.

• arformoterol

  arformoterol and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  arformoterol and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  olanzapine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• aripiprazole

  aripiprazole and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  aripiprazole and olanzapine both increase sedation. Use Caution/Monitor.
  
  aripiprazole and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• artemether/lumefantrine

  fluoxetine and artemether/lumefantrine both increase QTc interval. Modify Therapy/Monitor Closely.

• armodafinil

  armodafinil will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  olanzapine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• asenapine

  asenapine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  asenapine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  asenapine and olanzapine both increase sedation. Use Caution/Monitor.

• asenapine transdermal

  asenapine transdermal and olanzapine both increase sedation. Use Caution/Monitor.
  
  asenapine transdermal and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  asenapine transdermal and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• aspirin

  fluoxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• atomoxetine

  atomoxetine and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• aspirin rectal

  fluoxetine, aspirin rectal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• aspirin/citric acid/sodium bicarbonate

  fluoxetine, aspirin/citric acid/sodium bicarbonate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• atogepant

  fluoxetine will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atomoxetine

  fluoxetine will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Reduced initial doses of atomoxetine are recommended with strong CYP2D6 inhibitors.

• atracurium

  atracurium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atracurium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• atropine

  atropine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• atropine IV/IM

  olanzapine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  atropine IV/IM decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine IV/IM decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.

• avapritinib

  avapritinib and olanzapine both increase sedation. Use Caution/Monitor.
  
  olanzapine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• axitinib

  fluoxetine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  olanzapine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• azelastine

  azelastine and olanzapine both increase sedation. Use Caution/Monitor.

• bedaquiline

  fluoxetine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely

• azithromycin

  azithromycin increases toxicity of olanzapine by QTc interval. Use Caution/Monitor.

• baclofen

  baclofen and olanzapine both increase sedation. Use Caution/Monitor.

• bedaquiline

  olanzapine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely

• belladonna alkaloids

  belladonna alkaloids decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  belladonna alkaloids decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of belladonna alkaloids by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• belladonna and opium

  belladonna and opium and olanzapine both increase sedation. Use Caution/Monitor.
  
  belladonna and opium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  belladonna and opium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• benazepril

  olanzapine, benazepril. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Enhanced hypotensive effects.

• benperidol

  benperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  benperidol and olanzapine both increase sedation. Use Caution/Monitor.

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.
  
  benzhydrocodone/acetaminophen and olanzapine both increase sedation. Use Caution/Monitor.

• benzphetamine

  olanzapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• betrixaban

  fluoxetine increases effects of betrixaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• benztropine

  olanzapine increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .

• bosentan

  fluoxetine will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• brexanolone

  brexanolone, olanzapine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brexpiprazole

  fluoxetine will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP2D6 inhibitors. If also administered with a strong/moderate CYP3A4 inhibitor, administer a quarter of brexpiprazole dose. NOTE: In MDD clinical trials, brexpiprazole dosage was not adjusted for strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine); thus, CYP considerations are already factored into general dosing recommendations and brexpiprazole may be administered without dosage adjustment in patients with MDD.
  
  brexpiprazole and olanzapine both increase sedation. Use Caution/Monitor.

• brimonidine

  brimonidine and olanzapine both increase sedation. Use Caution/Monitor.

• buprenorphine subdermal implant

  fluoxetine, buprenorphine subdermal implant. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.

• brivaracetam

  brivaracetam and olanzapine both increase sedation. Use Caution/Monitor.

• brompheniramine

  brompheniramine and olanzapine both increase sedation. Use Caution/Monitor.

• buprenorphine

  buprenorphine and olanzapine both increase sedation. Use Caution/Monitor.

• buprenorphine buccal

  buprenorphine buccal and olanzapine both increase sedation. Use Caution/Monitor.

• buprenorphine subdermal implant

  buprenorphine subdermal implant and olanzapine both increase sedation. Use Caution/Monitor.

• buprenorphine, long-acting injection

  olanzapine increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.
  
  fluoxetine, buprenorphine, long-acting injection. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.

• bupropion

  bupropion will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• butabarbital

  butabarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  butabarbital and olanzapine both increase sedation. Use Caution/Monitor.

• butalbital

  butalbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  butalbital and olanzapine both increase sedation. Use Caution/Monitor.

• butorphanol

  butorphanol and olanzapine both increase sedation. Use Caution/Monitor.

• caffeine

  olanzapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• cannabidiol

  fluoxetine will increase the level or effect of cannabidiol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP2C19 inhibitor.
  
  cannabidiol, olanzapine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP1A2 induction and inhibition with the coadministration of CYP1A2 substrates and cannabidiol, consider reducing dosage adjustment of CYP1A2 substrates as clinically appropriate.
  
  cannabidiol will increase the level or effect of fluoxetine by decreasing metabolism. Modify Therapy/Monitor Closely. Cannabidiol may potentially inhibit CYP2C9 activity. Consider reducing the dose when concomitantly using CYP2C9 substrates.

• captopril

  olanzapine, captopril. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure. Monitor blood pressure.

• carbamazepine

  fluoxetine will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor plasma levels when used concomitantly

• carbamazepine

  carbamazepine will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• carbinoxamine

  carbinoxamine and olanzapine both increase sedation. Use Caution/Monitor.

• carisoprodol

  carisoprodol and olanzapine both increase sedation. Use Caution/Monitor.

• carvedilol

  fluoxetine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• celecoxib

  fluoxetine will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  celecoxib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine, celecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• chloral hydrate

  chloral hydrate and olanzapine both increase sedation. Use Caution/Monitor.

• chlordiazepoxide

  chlordiazepoxide and olanzapine both increase sedation. Use Caution/Monitor.

• chloroquine

  chloroquine increases toxicity of olanzapine by QTc interval. Use Caution/Monitor.

• chlorpheniramine

  chlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.

• chlorpromazine

  chlorpromazine and olanzapine both increase sedation. Use Caution/Monitor.
  
  chlorpromazine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  chlorpromazine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• chlorpropamide

  fluoxetine increases effects of chlorpropamide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, chlorpropamide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• chlorzoxazone

  chlorzoxazone and olanzapine both increase sedation. Use Caution/Monitor.

• choline magnesium trisalicylate

  fluoxetine, choline magnesium trisalicylate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• cigarette smoking

  cigarette smoking will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• cilostazol

  fluoxetine increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider decreasing cilostazol dose; moderate CYP2C19 inhibitors may increase serum levels of 3,4-dehydrocilostazol (active metabolite).

• cimetidine

  cimetidine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  cimetidine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• cinnarizine

  cinnarizine and olanzapine both increase sedation. Use Caution/Monitor.

• ciprofloxacin

  ciprofloxacin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• ciprofloxacin

  ciprofloxacin will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Olanzapine plasma concentrations may be elevated, increasing the risk of adverse reactions such as orthostatic hypotension or sedation. It is important to use caution and observe patient and adjust the olanzapine dosage as needed.

• cisatracurium

  cisatracurium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cisatracurium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• citalopram

  citalopram and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• clarithromycin

  clarithromycin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• clemastine

  clemastine and olanzapine both increase sedation. Use Caution/Monitor.

• clobazam

  olanzapine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
  
  clobazam will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.

• clomipramine

  olanzapine and clomipramine both increase sedation. Use Caution/Monitor.
  
  clomipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and clomipramine both increase QTc interval. Use Caution/Monitor.

• clonazepam

  clonazepam and olanzapine both increase sedation. Use Caution/Monitor.

• clonidine

  clonidine, fluoxetine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration enhances CNS depressant effects.

• clonidine

  clonidine, olanzapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

• clopidogrel

  fluoxetine increases effects of clopidogrel by pharmacodynamic synergism. Use Caution/Monitor. SSRIs affect platelet activation; coadministration of SSRIs with clopidogrel may increase the risk of bleeding.

• clorazepate

  clorazepate and olanzapine both increase sedation. Use Caution/Monitor.

• clozapine

  fluoxetine increases levels of clozapine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Plasma levels of clozapine may be increased, resulting in increased pharmacologic and toxic effects. Adjust clozapine dose as needed when initiating or discontinuing certain SSRIs. .
  
  clozapine and olanzapine both increase sedation. Use Caution/Monitor.
  
  clozapine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  clozapine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• cobicistat

  cobicistat will increase the level or effect of fluoxetine by Other (see comment). Use Caution/Monitor. Carefully titrate dose of the antidepressant to the desired effect, including using the lowest feasible initial or maintenance dose, and monitor its response during coadministration with SSRIs and cobicistat.

• codeine

  codeine and olanzapine both increase sedation. Use Caution/Monitor.

• cocaine topical

  fluoxetine and cocaine topical both increase serotonin levels. Modify Therapy/Monitor Closely.

• codeine

  fluoxetine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine

• crizotinib

  crizotinib and fluoxetine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

• cyclizine

  cyclizine and olanzapine both increase sedation. Use Caution/Monitor.
  
  cyclizine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cyclizine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of cyclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• cyclobenzaprine

  cyclobenzaprine and olanzapine both increase sedation. Use Caution/Monitor.
  
  cyclobenzaprine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cyclobenzaprine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of cyclobenzaprine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• cyproheptadine

  cyproheptadine decreases effects of fluoxetine by pharmacodynamic antagonism. Use Caution/Monitor. Cyproheptadine may diminish the serotonergic effect of SSRIs.
  
  cyproheptadine and olanzapine both increase sedation. Use Caution/Monitor.

• dantrolene

  dantrolene and olanzapine both increase sedation. Use Caution/Monitor.

• daridorexant

  fluoxetine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• daridorexant

  olanzapine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• darifenacin

  darifenacin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  darifenacin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• darunavir

  darunavir will increase the level or effect of fluoxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with SSRIs, TCAs, or trazodone may require dose titration of antidepressant to desired effect (eg, using the lowest feasible initial or maintenance dose). Monitor for antidepressant response.

• dasatinib

  dasatinib and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  dasatinib and fluoxetine both increase QTc interval. Use Caution/Monitor.

• deferasirox

  deferasirox will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• defibrotide

  defibrotide increases effects of fluoxetine by Other (see comment). Use Caution/Monitor. Comment: Defibrotide may enhance effects of platelet inhibitors.

• degarelix

  degarelix and fluoxetine both increase QTc interval. Use Caution/Monitor.

• desipramine

  olanzapine and desipramine both increase sedation. Use Caution/Monitor.
  
  olanzapine and desipramine both increase QTc interval. Use Caution/Monitor.
  
  desipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• desvenlafaxine

  desvenlafaxine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg

• deutetrabenazine

  olanzapine and deutetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely. The risk for parkinsonism, neuroleptic malignant syndrome, and akathisia may be increased by concomitant use of deutetrabenazine and dopamine antagonists or antipsychotics.
  
  olanzapine and deutetrabenazine both increase sedation. Use Caution/Monitor.
  
  deutetrabenazine and olanzapine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).

• deutetrabenazine

  fluoxetine will increase the level or effect of deutetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Strong CYP2D6 inhibitors increase the systemic exposure to the active dihydro-metabolites of deutetrabenazine by approximately 3-fold. Do not exceed 18 mg/dose and 36 mg/day of deutetrabenazine if coadministered with strong CYP2D6 inhibitors.
  
  deutetrabenazine and fluoxetine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).

• dexchlorpheniramine

  dexchlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.

• dexfenfluramine

  fluoxetine will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine and dexfenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  olanzapine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dexmedetomidine

  dexmedetomidine and olanzapine both increase sedation. Use Caution/Monitor.

• dextroamphetamine

  fluoxetine will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine and dextroamphetamine both increase serotonin levels. Modify Therapy/Monitor Closely.

• dexmethylphenidate

  olanzapine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextroamphetamine

  olanzapine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextroamphetamine transdermal

  fluoxetine, dextroamphetamine transdermal. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and concomitant serotonergic drug(s).
  
  fluoxetine will increase the level or effect of dextroamphetamine transdermal by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome, particularly during dextroamphetamine initiation and after a dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and CYP2D6 inhibitor.

• dextromethorphan

  dextromethorphan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• dextromoramide

  dextromoramide and olanzapine both increase sedation. Use Caution/Monitor.

• diamorphine

  diamorphine and olanzapine both increase sedation. Use Caution/Monitor.

• diazepam

  fluoxetine will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  diazepam and olanzapine both increase sedation. Use Caution/Monitor.

• diazepam intranasal

  fluoxetine will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
  
  diazepam intranasal, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.

• dicyclomine

  dicyclomine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  dicyclomine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• dichlorphenamide

  dichlorphenamide and fluoxetine both decrease serum potassium. Use Caution/Monitor.

• diclofenac

  fluoxetine will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, diclofenac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• diethylpropion

  olanzapine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• difelikefalin

  difelikefalin and olanzapine both increase sedation. Use Caution/Monitor.
  
  difelikefalin and fluoxetine both increase sedation. Use Caution/Monitor.

• difenoxin hcl

  difenoxin hcl and olanzapine both increase sedation. Use Caution/Monitor.

• diflunisal

  fluoxetine, diflunisal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• dihydroergotamine

  dihydroergotamine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and dihydroergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.

• dihydroergotamine intranasal

  fluoxetine and dihydroergotamine intranasal both increase serotonin levels. Modify Therapy/Monitor Closely.

• dimenhydrinate

  dimenhydrinate and olanzapine both increase sedation. Use Caution/Monitor.

• diphenhydramine

  diphenhydramine and olanzapine both increase sedation. Use Caution/Monitor.
  
  diphenhydramine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  diphenhydramine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• diphenoxylate hcl

  diphenoxylate hcl and olanzapine both increase sedation. Use Caution/Monitor.

• dipipanone

  dipipanone and olanzapine both increase sedation. Use Caution/Monitor.

• dobutamine

  olanzapine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dofetilide

  dofetilide increases toxicity of olanzapine by QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.
  
  dofetilide and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• dolasetron

  dolasetron and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  dolasetron and olanzapine both increase QTc interval. Use Caution/Monitor.

• donepezil

  donepezil and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  fluoxetine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  donepezil and fluoxetine both increase QTc interval. Use Caution/Monitor.

• dopamine

  olanzapine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• doxepin

  doxepin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• dopexamine

  olanzapine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dosulepin

  olanzapine and dosulepin both increase sedation. Use Caution/Monitor.

• doxepin

  olanzapine and doxepin both increase sedation. Use Caution/Monitor.
  
  doxepin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• doxylamine

  doxylamine and olanzapine both increase sedation. Use Caution/Monitor.

• dronedarone

  dronedarone and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• droperidol

  droperidol and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  droperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  droperidol and olanzapine both increase sedation. Use Caution/Monitor.

• edoxaban

  fluoxetine increases effects of edoxaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• efavirenz

  efavirenz and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• efavirenz

  efavirenz and fluoxetine both increase QTc interval. Use Caution/Monitor.

• eletriptan

  eletriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  eletriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.

• eliglustat

  eliglustat increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.

• ephedrine

  olanzapine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• eluxadoline

  fluoxetine increases levels of eluxadoline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2D6 inhibitors.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
  
  elvitegravir/cobicistat/emtricitabine/tenofovir DF decreases levels of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Elvitegravir is a moderate CYP2C9 inducer.

• encainide

  fluoxetine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• epinephrine

  olanzapine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  epinephrine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• epinephrine racemic

  olanzapine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  epinephrine racemic and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• ergoloid mesylates

  ergoloid mesylates, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• ergotamine

  fluoxetine and ergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.

• ergotamine

  ergotamine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• eribulin

  eribulin and fluoxetine both increase QTc interval. Use Caution/Monitor.

• erythromycin base

  erythromycin base and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  erythromycin base will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• erythromycin ethylsuccinate

  erythromycin ethylsuccinate and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  erythromycin ethylsuccinate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• erythromycin lactobionate

  erythromycin lactobionate and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  erythromycin lactobionate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• erythromycin stearate

  erythromycin stearate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  erythromycin stearate and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• escitalopram

  escitalopram increases toxicity of olanzapine by QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.
  
  escitalopram and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• esketamine intranasal

  esketamine intranasal, olanzapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• ethotoin

  fluoxetine will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• estazolam

  estazolam and olanzapine both increase sedation. Use Caution/Monitor.

• ethanol

  olanzapine and ethanol both increase sedation. Use Caution/Monitor.

• ethinylestradiol

  ethinylestradiol will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• etodolac

  fluoxetine, etodolac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• etravirine

  fluoxetine will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• exenatide injectable solution

  olanzapine, exenatide injectable solution. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• exenatide injectable suspension

  olanzapine, exenatide injectable suspension. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• ezogabine

  ezogabine and fluoxetine both increase QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.

• fedratinib

  fedratinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.

• fenbufen

  fluoxetine, fenbufen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• fenfluramine

  olanzapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
  
  fenfluramine, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
  
  olanzapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.

• fenoprofen

  fluoxetine, fenoprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• fentanyl

  fentanyl, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• fesoterodine

  fesoterodine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fesoterodine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  olanzapine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• fexinidazole

  fexinidazole will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• finerenone

  fluoxetine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

• finerenone

  olanzapine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

• fingolimod

  fingolimod and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  fingolimod and fluoxetine both increase QTc interval. Use Caution/Monitor.

• fish oil triglycerides

  fish oil triglycerides will increase the level or effect of fluoxetine by anticoagulation. Use Caution/Monitor. Prolonged bleeding reported in patients taking antiplatelet agents or anticoagulants and oral omega-3 fatty acids. Periodically monitor bleeding time in patients receiving fish oil triglycerides and concomitant antiplatelet agents or anticoagulants.

• flavoxate

  flavoxate decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  flavoxate decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• flecainide

  olanzapine and flecainide both increase QTc interval. Use Caution/Monitor.
  
  flecainide and fluoxetine both increase QTc interval. Use Caution/Monitor.

• flibanserin

  flibanserin, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  olanzapine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.
  
  fluoxetine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

• fluconazole

  olanzapine and fluconazole both increase QTc interval. Use Caution/Monitor.
  
  fluconazole and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• fluoxetine

  olanzapine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• flurbiprofen

  fluoxetine will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, flurbiprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• fluphenazine

  fluphenazine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and olanzapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• flurazepam

  flurazepam and olanzapine both increase sedation. Use Caution/Monitor.

• fluvastatin

  fluoxetine will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fondaparinux

  fluoxetine increases effects of fondaparinux by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• formoterol

  fluoxetine and formoterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system
  
  olanzapine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• foscarnet

  fluoxetine and foscarnet both increase QTc interval. Use Caution/Monitor.

• fostemsavir

  olanzapine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

• fosphenytoin

  fluoxetine will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fostemsavir

  fluoxetine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

• frovatriptan

  frovatriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  frovatriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.

• gabapentin

  gabapentin, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• gadobenate

  gadobenate and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• gabapentin enacarbil

  gabapentin enacarbil, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• galantamine

  fluoxetine will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• ganaxolone

  olanzapine and ganaxolone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and ganaxolone both increase sedation. Use Caution/Monitor.

• gemifloxacin

  gemifloxacin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  gemifloxacin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• gemtuzumab

  olanzapine and gemtuzumab both increase QTc interval. Use Caution/Monitor.

• glimepiride

  fluoxetine increases effects of glimepiride by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• gilteritinib

  gilteritinib and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• glimepiride

  olanzapine, glimepiride. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• glipizide

  fluoxetine increases effects of glipizide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, glipizide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• glyburide

  fluoxetine increases effects of glyburide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, glyburide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• glycopyrrolate

  olanzapine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• granisetron

  granisetron and fluoxetine both increase QTc interval. Use Caution/Monitor.

• glycopyrrolate inhaled

  glycopyrrolate inhaled decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  glycopyrrolate inhaled decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• granisetron

  granisetron and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• green tea

  green tea, fluoxetine. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of bleeding.

• guanfacine

  guanfacine, olanzapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

• haloperidol

  haloperidol and olanzapine both increase sedation. Use Caution/Monitor.
  
  haloperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluoxetine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.
  
  haloperidol and olanzapine both increase QTc interval. Use Caution/Monitor.

• henbane

  henbane decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  henbane decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hydrocodone

  hydrocodone, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.

• homatropine

  homatropine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  homatropine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hydromorphone

  hydromorphone and olanzapine both increase sedation. Use Caution/Monitor.

• hydroxyzine

  hydroxyzine and olanzapine both increase sedation. Use Caution/Monitor.
  
  hydroxyzine and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• hyoscyamine

  hyoscyamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  hyoscyamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hyoscyamine spray

  olanzapine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  hyoscyamine spray decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  hyoscyamine spray decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.

• ibrutinib

  ibrutinib will increase the level or effect of fluoxetine by anticoagulation. Use Caution/Monitor. Ibrutinib may increase the risk of hemorrhage in patients receiving antiplatelet or anticoagulant therapies and monitor for signs of bleeding.

• ibuprofen

  fluoxetine will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, ibuprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ibuprofen IV

  fluoxetine will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, ibuprofen IV. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• iloperidone

  iloperidone and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluoxetine and iloperidone both increase QTc interval. Use Caution/Monitor.
  
  iloperidone and olanzapine both increase sedation. Use Caution/Monitor.

• imatinib

  imatinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• imipramine

  olanzapine and imipramine both increase sedation. Use Caution/Monitor.
  
  olanzapine and imipramine both increase QTc interval. Use Caution/Monitor.

• imipramine

  imipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• incobotulinumtoxinA

  olanzapine increases effects of incobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• indacaterol, inhaled

  indacaterol, inhaled and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• indomethacin

  fluoxetine, indomethacin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• insulin aspart

  fluoxetine increases effects of insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.
  
  olanzapine, insulin aspart. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• insulin aspart protamine/insulin aspart

  fluoxetine increases effects of insulin aspart protamine/insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  olanzapine decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.

• insulin degludec

  fluoxetine, insulin degludec. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  fluoxetine increases effects of insulin degludec by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec/insulin aspart

  fluoxetine, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  olanzapine decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.

• insulin detemir

  olanzapine, insulin detemir. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin detemir by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin glargine

  olanzapine, insulin glargine. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin glargine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin glulisine

  olanzapine, insulin glulisine. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin glulisine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin inhaled

  olanzapine decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.
  
  fluoxetine, insulin inhaled. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  fluoxetine increases effects of insulin inhaled by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin isophane human/insulin regular human

  fluoxetine increases effects of insulin isophane human/insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  olanzapine, insulin NPH. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• insulin lispro

  olanzapine, insulin lispro. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• insulin lispro

  fluoxetine increases effects of insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro protamine/insulin lispro

  fluoxetine increases effects of insulin lispro protamine/insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  fluoxetine increases effects of insulin NPH by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin regular human

  olanzapine, insulin regular human. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• ipratropium

  ipratropium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  ipratropium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• isavuconazonium sulfate

  fluoxetine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isavuconazonium sulfate

  olanzapine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isoniazid

  fluoxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• isoproterenol

  olanzapine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• itraconazole

  itraconazole and fluoxetine both increase QTc interval. Use Caution/Monitor.

• isradipine

  olanzapine and isradipine both increase QTc interval. Use Caution/Monitor.

• itraconazole

  itraconazole and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• ivacaftor

  fluoxetine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .
  
  olanzapine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

• ketoconazole

  fluoxetine and ketoconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• ketotifen, ophthalmic

  olanzapine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

• ketoprofen

  fluoxetine, ketoprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ketorolac

  fluoxetine, ketorolac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ketorolac intranasal

  fluoxetine, ketorolac intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• L-tryptophan

  fluoxetine and L-tryptophan both increase serotonin levels. Modify Therapy/Monitor Closely.

• lamotrigine

  lamotrigine increases toxicity of fluoxetine by unspecified interaction mechanism. Modify Therapy/Monitor Closely. CNS depressants may increase the toxic effects of selective serotonin reuptake inhibitors; psychomotor impairment may be enhanced.

• lapatinib

  fluoxetine and lapatinib both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and lapatinib both increase QTc interval. Use Caution/Monitor.

• lasmiditan

  fluoxetine increases effects of lasmiditan by serotonin levels. Use Caution/Monitor. Coadministration may increase risk of serotonin syndrome.
  
  lasmiditan, olanzapine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
  
  lasmiditan, fluoxetine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• lemborexant

  lemborexant, olanzapine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
  
  lemborexant, fluoxetine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
  
  olanzapine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.
  
  fluoxetine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

• lenvatinib

  fluoxetine and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.

• levalbuterol

  olanzapine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• levalbuterol

  fluoxetine and levalbuterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• levofloxacin

  olanzapine and levofloxacin both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and levofloxacin both increase QTc interval. Use Caution/Monitor.

• levoketoconazole

  fluoxetine and levoketoconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• levomilnacipran

  levomilnacipran, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• levorphanol

  levorphanol and olanzapine both increase sedation. Use Caution/Monitor.

• linezolid

  linezolid, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• liraglutide

  olanzapine, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• lisdexamfetamine

  olanzapine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine, lisdexamfetamine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue along with concomitant serotonergic drug(s).

• lithium

  lithium and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  lithium, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and lithium both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  lithium and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• lofepramine

  olanzapine and lofepramine both increase sedation. Use Caution/Monitor.

• lofexidine

  fluoxetine will increase the level or effect of lofexidine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Concomitant use of lofexidine with strong CYP2D6 inhibitors may increase lofexidine plasma levels. Monitor for symptoms of orthostasis and bradycardia if coadministered with a CYP2D6 inhibitor. Consider lofexidine dose reduction.
  
  fluoxetine and lofexidine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended.

• lofexidine

  olanzapine and lofexidine both increase sedation. Use Caution/Monitor.
  
  olanzapine and lofexidine both increase QTc interval. Use Caution/Monitor.

• lomitapide

  olanzapine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.
  
  fluoxetine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

• loperamide

  olanzapine and loperamide both increase QTc interval. Use Caution/Monitor.

• loratadine

  fluoxetine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• loprazolam

  loprazolam and olanzapine both increase sedation. Use Caution/Monitor.

• lorazepam

  lorazepam and olanzapine both increase sedation. Use Caution/Monitor.

• lorcaserin

  lorcaserin will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  lorcaserin, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• lormetazepam

  lormetazepam and olanzapine both increase sedation. Use Caution/Monitor.

• lornoxicam

  fluoxetine, lornoxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• losartan

  fluoxetine will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• loxapine

  loxapine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  loxapine and olanzapine both increase sedation. Use Caution/Monitor.

• loxapine inhaled

  loxapine inhaled and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  loxapine inhaled and olanzapine both increase sedation. Use Caution/Monitor.

• lsd

  fluoxetine and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.

• lumacaftor/ivacaftor

  lumacaftor/ivacaftor, fluoxetine. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C9 substrates. .

• lumefantrine

  fluoxetine and lumefantrine both increase QTc interval. Modify Therapy/Monitor Closely.

• lurasidone

  lurasidone, olanzapine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
  
  lurasidone, fluoxetine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• maprotiline

  maprotiline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and maprotiline both increase sedation. Use Caution/Monitor.

• maraviroc

  maraviroc, olanzapine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.

• meclofenamate

  fluoxetine, meclofenamate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• marijuana

  olanzapine and marijuana both increase sedation. Use Caution/Monitor.

• mavacamten

  olanzapine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• meclizine

  meclizine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  meclizine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• mefenamic acid

  fluoxetine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• melatonin

  olanzapine and melatonin both increase sedation. Use Caution/Monitor.

• meloxicam

  fluoxetine will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, meloxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• meperidine

  meperidine and olanzapine both increase sedation. Use Caution/Monitor.
  
  meperidine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• meprobamate

  olanzapine and meprobamate both increase sedation. Use Caution/Monitor.

• metaproterenol

  olanzapine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metaxalone

  metaxalone and olanzapine both increase sedation. Use Caution/Monitor.

• metformin

  olanzapine, metformin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of metformin by pharmacodynamic synergism. Use Caution/Monitor.

• methadone

  fluoxetine and methadone both increase QTc interval. Use Caution/Monitor.
  
  methadone and olanzapine both increase sedation. Use Caution/Monitor.
  
  methadone, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• methamphetamine

  olanzapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methylphenidate transdermal

  methylphenidate transdermal will increase the level or effect of fluoxetine by decreasing metabolism. Modify Therapy/Monitor Closely. Consider decreasing the dose of these drugs when given coadministered with methylphenidate. Monitor for drug toxiticities when initiating or discontinuing methylphenidate.

• methocarbamol

  methocarbamol and olanzapine both increase sedation. Use Caution/Monitor.

• methscopolamine

  methscopolamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  methscopolamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• methylenedioxymethamphetamine

  olanzapine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methylergonovine

  methylergonovine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• methylphenidate

  olanzapine increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.

• metoclopramide

  olanzapine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

• mexiletine

  mexiletine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• midazolam

  midazolam and olanzapine both increase sedation. Use Caution/Monitor.

• midazolam intranasal

  midazolam intranasal, fluoxetine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
  
  olanzapine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.
  
  fluoxetine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.
  
  midazolam intranasal, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• midodrine

  olanzapine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mifepristone

  mifepristone, fluoxetine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.

• mifepristone

  mifepristone, olanzapine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.

• miglitol

  olanzapine, miglitol. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• milnacipran

  milnacipran, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• mipomersen

  mipomersen, fluoxetine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mirabegron

  mirabegron will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• mirtazapine

  olanzapine and mirtazapine both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  mirtazapine and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  olanzapine and mirtazapine both increase sedation. Use Caution/Monitor.

• modafinil

  modafinil will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  olanzapine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• morphine

  fluoxetine and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.

• morphine

  morphine and olanzapine both increase sedation. Use Caution/Monitor.

• motherwort

  olanzapine and motherwort both increase sedation. Use Caution/Monitor.

• moxifloxacin

  fluoxetine and moxifloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

• moxonidine

  olanzapine and moxonidine both increase sedation. Use Caution/Monitor.

• nabilone

  olanzapine and nabilone both increase sedation. Use Caution/Monitor.

• nabumetone

  fluoxetine, nabumetone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• nalbuphine

  nalbuphine and olanzapine both increase sedation. Use Caution/Monitor.

• naproxen

  fluoxetine, naproxen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• naratriptan

  naratriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  naratriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• nateglinide

  olanzapine, nateglinide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• nifedipine

  fluoxetine will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider initiating nifedipine at the lowest dose available if given concomitantly with this medication

• norepinephrine

  olanzapine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nilotinib

  fluoxetine and nilotinib both increase QTc interval. Modify Therapy/Monitor Closely.

• nitisinone

  nitisinone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Nitisinone inhibits CYP2C9. Caution if CYP2C9 substrate coadministered, particularly those with a narrow therapeutic index.

• nortriptyline

  olanzapine and nortriptyline both increase sedation. Use Caution/Monitor.
  
  olanzapine and nortriptyline both increase QTc interval. Use Caution/Monitor.
  
  nortriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• octreotide

  fluoxetine and octreotide both increase QTc interval. Modify Therapy/Monitor Closely.

• ofloxacin

  olanzapine and ofloxacin both increase QTc interval. Use Caution/Monitor.

• octreotide (Antidote)

  fluoxetine and octreotide (Antidote) both increase QTc interval. Modify Therapy/Monitor Closely.

• ofloxacin

  fluoxetine and ofloxacin both increase QTc interval. Use Caution/Monitor.

• olanzapine

  olanzapine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• oliceridine

  fluoxetine, oliceridine. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely.
  
  fluoxetine will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
  
  oliceridine, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• olodaterol inhaled

  fluoxetine and olodaterol inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• onabotulinumtoxinA

  onabotulinumtoxinA decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  onabotulinumtoxinA decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• opium tincture

  opium tincture and olanzapine both increase sedation. Use Caution/Monitor.

• orphenadrine

  orphenadrine and olanzapine both increase sedation. Use Caution/Monitor.

• osilodrostat

  osilodrostat and olanzapine both increase QTc interval. Use Caution/Monitor.
  
  osilodrostat and fluoxetine both increase QTc interval. Use Caution/Monitor.

• osimertinib

  osimertinib and olanzapine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.
  
  osimertinib and fluoxetine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.

• oxaliplatin

  oxaliplatin will increase the level or effect of olanzapine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.

• oxaprozin

  fluoxetine, oxaprozin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• oxazepam

  oxazepam and olanzapine both increase sedation. Use Caution/Monitor.

• oxybutynin

  oxybutynin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxybutynin topical

  oxybutynin topical decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin topical decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxybutynin transdermal

  oxybutynin transdermal decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin transdermal decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxycodone

  oxycodone and olanzapine both increase sedation. Use Caution/Monitor.

• oxymorphone

  oxymorphone and olanzapine both increase sedation. Use Caution/Monitor.

• ozanimod

  ozanimod and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.
  
  ozanimod and olanzapine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.

• paliperidone

  olanzapine and paliperidone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and paliperidone both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and paliperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

• pancuronium

  pancuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  pancuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• parecoxib

  fluoxetine will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, parecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• papaveretum

  papaveretum and olanzapine both increase sedation. Use Caution/Monitor.

• papaverine

  olanzapine and papaverine both increase sedation. Use Caution/Monitor.

• paroxetine

  paroxetine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and paroxetine both increase QTc interval. Use Caution/Monitor.

• pasireotide

  olanzapine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluoxetine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.

• peginterferon alfa 2a

  peginterferon alfa 2a will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• peginterferon alfa 2b

  peginterferon alfa 2b, fluoxetine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.

• pentazocine

  pentazocine and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.

• pentobarbital

  pentobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  pentobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• pentoxifylline

  pentoxifylline increases toxicity of fluoxetine by anticoagulation. Use Caution/Monitor. May increase bleeding.

• perhexiline

  fluoxetine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• perphenazine

  olanzapine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and perphenazine both increase sedation. Use Caution/Monitor.
  
  olanzapine and perphenazine both increase QTc interval. Use Caution/Monitor.

• phendimetrazine

  olanzapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenelzine

  phenelzine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• phenobarbital

  phenobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  phenobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• phentermine

  olanzapine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine

  olanzapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine PO

  olanzapine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• phenytoin

  fluoxetine will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pholcodine

  olanzapine and pholcodine both increase sedation. Use Caution/Monitor.

• pimozide

  olanzapine and pimozide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and pimozide both increase sedation. Use Caution/Monitor.

• pioglitazone

  olanzapine, pioglitazone. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• pipemidic acid

  pipemidic acid will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• pirbuterol

  olanzapine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine and pirbuterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• piroxicam

  fluoxetine will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, piroxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• posaconazole

  olanzapine and posaconazole both increase QTc interval. Use Caution/Monitor.

• pitolisant

  fluoxetine will increase the level or effect of pitolisant by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If coadministered with strong CYP2D6 inhibitors, initiate pitolisant at 8.9 mg/day and increase after 7 days to maximum of 17.8 mg/day. For patients currently taking pitolisant, reduce pitolisant dose by half upon initiating strong CYP2D6 inhibitors.

• posaconazole

  fluoxetine and posaconazole both increase QTc interval. Use Caution/Monitor.

• pralidoxime

  pralidoxime decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  pralidoxime decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• pramlintide

  olanzapine, pramlintide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• pregabalin

  pregabalin, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• primaquine

  primaquine and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and primaquine both increase QTc interval. Use Caution/Monitor.

• primidone

  primidone will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  primidone and olanzapine both increase sedation. Use Caution/Monitor.

• prochlorperazine

  fluoxetine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  prochlorperazine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• procarbazine

  procarbazine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• prochlorperazine

  olanzapine and prochlorperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and prochlorperazine both increase sedation. Use Caution/Monitor.
  
  olanzapine and prochlorperazine both decrease QTc interval. Use Caution/Monitor.

• promazine

  fluoxetine will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  promazine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• promethazine

  promethazine and olanzapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and promethazine both decrease QTc interval. Use Caution/Monitor.
  
  promethazine and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  promethazine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• propantheline

  propantheline decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  propantheline decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• protriptyline

  protriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• propofol

  propofol and olanzapine both increase sedation. Use Caution/Monitor.

• propylhexedrine

  olanzapine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• protriptyline

  olanzapine and protriptyline both increase sedation. Use Caution/Monitor.
  
  olanzapine and protriptyline both increase QTc interval. Use Caution/Monitor.

• quazepam

  quazepam and olanzapine both increase sedation. Use Caution/Monitor.

• quetiapine

  quetiapine, fluoxetine. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.
  
  olanzapine and quetiapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

• quinine

  fluoxetine and quinine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and quinine both increase QTc interval. Use Caution/Monitor.

• ramelteon

  fluoxetine will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  olanzapine and ramelteon both increase sedation. Use Caution/Monitor.

• ranolazine

  fluoxetine and ranolazine both increase QTc interval. Use Caution/Monitor.

• rapacuronium

  rapacuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  rapacuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• remifentanil

  remifentanil, fluoxetine. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely.

• remimazolam

  remimazolam, fluoxetine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.
  
  remimazolam, olanzapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.

• repaglinide

  olanzapine, repaglinide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• rilpivirine

  rilpivirine increases toxicity of fluoxetine by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsades de Pointes.

• rifampin

  rifampin will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• rilpivirine

  olanzapine and rilpivirine both increase QTc interval. Use Caution/Monitor.

• rimabotulinumtoxinB

  olanzapine, rimabotulinumtoxinB. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• risperidone

  olanzapine and risperidone both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and risperidone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and risperidone both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

• ritonavir

  ritonavir decreases levels of olanzapine by increasing metabolism. Use Caution/Monitor.

• rivaroxaban

  fluoxetine increases effects of rivaroxaban by pharmacodynamic synergism. Use Caution/Monitor. Combination may increase risk of bleeding.

• rizatriptan

  rizatriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.

• rocuronium

  rocuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  rocuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• rolapitant

  rolapitant will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.

• romidepsin

  olanzapine and romidepsin both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and romidepsin both increase QTc interval. Use Caution/Monitor.

• rosiglitazone

  olanzapine, rosiglitazone. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• rucaparib

  rucaparib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C9 substrates, if clinically indicated.

• rucaparib

  rucaparib will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP1A2 substrates, if clinically indicated.

• safinamide

  fluoxetine, safinamide. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Monitor patients for symptoms of serotonin syndrome if SSRIs are coadministered with safinamide.

• salicylates (non-asa)

  fluoxetine, salicylates (non-asa). Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• salmeterol

  fluoxetine and salmeterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system
  
  olanzapine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salsalate

  fluoxetine, salsalate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• saxagliptin

  olanzapine, saxagliptin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• SAMe

  fluoxetine and SAMe both increase serotonin levels. Modify Therapy/Monitor Closely.

• saquinavir

  saquinavir and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• scopolamine

  scopolamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  scopolamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of scopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• scullcap

  olanzapine and scullcap both increase sedation. Use Caution/Monitor.

• secobarbital

  secobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  secobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• selegiline

  selegiline, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• selpercatinib

  selpercatinib increases toxicity of olanzapine by QTc interval. Use Caution/Monitor.
  
  selpercatinib increases toxicity of fluoxetine by QTc interval. Use Caution/Monitor.

• sertraline

  olanzapine and sertraline both increase QTc interval. Use Caution/Monitor.
  
  sertraline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• shepherd's purse

  olanzapine and shepherd's purse both increase sedation. Use Caution/Monitor.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases effects of fluoxetine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of seizures when using bowel preps together with drugs that lower the seizure threshold.

• sitagliptin

  olanzapine, sitagliptin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• smoking

  smoking will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases effects of olanzapine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.

• sodium sulfate/potassium sulfate/magnesium sulfate

  sodium sulfate/potassium sulfate/magnesium sulfate increases effects of fluoxetine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of seizures when using bowel preps together with drugs that lower the seizure threshold.
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases effects of olanzapine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.

• sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol

  fluoxetine, sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol. Other (see comment). Use Caution/Monitor. Comment: Caution when bowel preps are used with drugs that cause SIADH or NSAIDs; increased risk for water retention or electrolyte imbalance.

• solifenacin

  solifenacin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  solifenacin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  olanzapine and solifenacin both increase QTc interval. Use Caution/Monitor.

• solifenacin

  solifenacin and fluoxetine both increase QTc interval. Use Caution/Monitor.

• sorafenib

  sorafenib and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  sorafenib and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• sparsentan

  sparsentan will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C9 inducer) decreases exposure of CYP2C9 substrates and reduces efficacy related to these substrates.

• stiripentol

  stiripentol, olanzapine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP1A2 inhibitor and inducer. Monitor CYP1A2 substrates coadministered with stiripentol for increased or decreased effects. CYP1A2 substrates may require dosage adjustment.
  
  stiripentol, olanzapine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

• sufentanil

  sufentanil and olanzapine both increase sedation. Use Caution/Monitor.

• sufentanil SL

  sufentanil SL, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.

• sulfamethoxazole

  fluoxetine will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• sulfasalazine

  fluoxetine, sulfasalazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• sulindac

  fluoxetine, sulindac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• sumatriptan

  sumatriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  sumatriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.

• sumatriptan intranasal

  sumatriptan intranasal, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  sumatriptan intranasal and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.

• sunitinib

  olanzapine and sunitinib both increase QTc interval. Use Caution/Monitor.
  
  sunitinib and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• tacrolimus

  tacrolimus and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and tacrolimus both increase QTc interval. Use Caution/Monitor.

• tamoxifen

  fluoxetine will decrease the level or effect of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.

• tapentadol

  tapentadol and olanzapine both increase sedation. Use Caution/Monitor.

• tamsulosin

  fluoxetine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• tapentadol

  fluoxetine and tapentadol both increase serotonin levels. Modify Therapy/Monitor Closely.

• tazemetostat

  olanzapine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• telavancin

  fluoxetine and telavancin both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and telavancin both increase QTc interval. Use Caution/Monitor.

• temazepam

  temazepam and olanzapine both increase sedation. Use Caution/Monitor.

• terbinafine

  terbinafine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.

• terbutaline

  fluoxetine and terbutaline both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system
  
  olanzapine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• teriflunomide

  teriflunomide decreases levels of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• tetrabenazine

  fluoxetine increases effects of tetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Decrease tetrabenazine dose by 50% when coadministered with strong CYP2D6 inhibitors.

• tetrabenazine

  olanzapine and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.

• thioridazine

  olanzapine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and thioridazine both increase sedation. Use Caution/Monitor.

• thiothixene

  olanzapine and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  thiothixene and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and thiothixene both increase sedation. Use Caution/Monitor.

• tinidazole

  fluoxetine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  olanzapine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tiotropium

  tiotropium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tiotropium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• tolazamide

  fluoxetine increases effects of tolazamide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• tobacco use

  tobacco use will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• tolazamide

  olanzapine, tolazamide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• tolbutamide

  fluoxetine increases effects of tolbutamide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  fluoxetine will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  olanzapine, tolbutamide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• tolfenamic acid

  fluoxetine, tolfenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• tolterodine

  tolterodine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tolterodine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• tolmetin

  fluoxetine, tolmetin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• topiramate

  olanzapine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• toremifene

  toremifene and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• tramadol

  tramadol and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine and tramadol both increase serotonin levels. Modify Therapy/Monitor Closely.

• tranylcypromine

  tranylcypromine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• trazodone

  trazodone and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• trazodone

  olanzapine and trazodone both increase sedation. Use Caution/Monitor.

• triazolam

  triazolam and olanzapine both increase sedation. Use Caution/Monitor.

• triclabendazole

  triclabendazole and olanzapine both increase QTc interval. Use Caution/Monitor.
  
  triclabendazole and fluoxetine both increase QTc interval. Use Caution/Monitor.

• triclofos

  triclofos and olanzapine both increase sedation. Use Caution/Monitor.

• trifluoperazine

  fluoxetine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  trifluoperazine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• trifluoperazine

  olanzapine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and trifluoperazine both increase sedation. Use Caution/Monitor.
  
  olanzapine and trifluoperazine both decrease QTc interval. Use Caution/Monitor.

• trihexyphenidyl

  olanzapine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

• trimethoprim

  fluoxetine and trimethoprim both increase QTc interval. Use Caution/Monitor.

• trimipramine

  olanzapine and trimipramine both increase QTc interval. Use Caution/Monitor.
  
  trimipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and trimipramine both increase sedation. Use Caution/Monitor.

• triprolidine

  triprolidine and olanzapine both increase sedation. Use Caution/Monitor.

• tropisetron

  fluoxetine will increase the level or effect of tropisetron by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine and tropisetron both increase QTc interval. Use Caution/Monitor.

• trospium chloride

  trospium chloride decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  trospium chloride decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• umeclidinium bromide/vilanterol inhaled

  fluoxetine and umeclidinium bromide/vilanterol inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• valbenazine

  valbenazine and olanzapine both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of valbenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Consider reducing valbenazine dose based on tolerability if coadministered with a strong CYP2D6 inhibitor.
  
  valbenazine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• valerian

  valerian and fluoxetine both increase sedation. Use Caution/Monitor.

• vardenafil

  olanzapine and vardenafil both increase QTc interval. Use Caution/Monitor.

• vardenafil

  vardenafil and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• vecuronium

  vecuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  vecuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• venlafaxine

  fluoxetine and venlafaxine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and venlafaxine both decrease QTc interval. Use Caution/Monitor.
  
  venlafaxine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• verapamil

  verapamil will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• vilanterol/fluticasone furoate inhaled

  fluoxetine and vilanterol/fluticasone furoate inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• vilazodone

  vilazodone, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• voclosporin

  voclosporin, olanzapine. Either increases effects of the other by QTc interval. Use Caution/Monitor.
  
  voclosporin, fluoxetine. Either increases effects of the other by QTc interval. Use Caution/Monitor.

• vorapaxar

  fluoxetine, vorapaxar. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive antiplatelet effect may occur; SSRIs and SNRIs may cause platelet serotonin depletion .

• voriconazole

  olanzapine and voriconazole both increase QTc interval. Use Caution/Monitor.

• voriconazole

  fluoxetine will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine and voriconazole both increase QTc interval. Use Caution/Monitor.

• vorinostat

  olanzapine and vorinostat both increase QTc interval. Use Caution/Monitor.
  
  vorinostat and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• warfarin

  fluoxetine, warfarin. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Serotonin release by platelets plays an important role in hemostasis. SSRIs and SNRIs may increase anticoagulation effect of warfarin. .

• xylometazoline

  olanzapine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• yohimbine

  olanzapine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• zanubrutinib

  fluoxetine, zanubrutinib. Either increases effects of the other by anticoagulation. Modify Therapy/Monitor Closely. Zanubrutinib-induced cytopenias increases risk of hemorrhage. Coadministration of zanubritinib with antiplatelets or anticoagulants may further increase this risk.

• ziconotide

  olanzapine and ziconotide both increase sedation. Use Caution/Monitor.

• zileuton

  zileuton will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• ziprasidone

  olanzapine and ziprasidone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and ziprasidone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and ziprasidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

• zolmitriptan

  zolmitriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  zolmitriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.

• zotepine

  olanzapine and zotepine both increase sedation. Use Caution/Monitor.
  
  olanzapine and zotepine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluoxetine increases levels of zotepine by decreasing metabolism. Use Caution/Monitor.

Minor (43)

• almotriptan

  fluoxetine, almotriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• azithromycin

  azithromycin and fluoxetine both increase QTc interval. Minor/Significance Unknown.

• brimonidine

  brimonidine increases effects of olanzapine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

• bumetanide

  bumetanide, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• celandine

  celandine decreases effects of fluoxetine by pharmacodynamic antagonism. Minor/Significance Unknown. Based on animal studies.

• chasteberry

  chasteberry decreases effects of olanzapine by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).

• chloroquine

  chloroquine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
  
  chloroquine increases toxicity of fluoxetine by QTc interval. Minor/Significance Unknown.

• codeine

  fluoxetine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• darifenacin

  darifenacin will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• dexmethylphenidate

  dexmethylphenidate increases effects of fluoxetine by decreasing metabolism. Minor/Significance Unknown.

• diphenhydramine

  diphenhydramine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• dronedarone

  dronedarone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• duloxetine

  duloxetine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• eletriptan

  fluoxetine, eletriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• esomeprazole

  fluoxetine will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• ethacrynic acid

  ethacrynic acid, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• ethanol

  ethanol, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.

• eucalyptus

  olanzapine and eucalyptus both increase sedation. Minor/Significance Unknown.

• frovatriptan

  fluoxetine, frovatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• furosemide

  furosemide, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• lansoprazole

  fluoxetine will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• lithium

  fluoxetine, lithium. Mechanism: unknown. Minor/Significance Unknown. Risk of neurotoxicity.

• losartan

  fluoxetine decreases effects of losartan by decreasing metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• maraviroc

  maraviroc will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• marijuana

  marijuana will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• naratriptan

  fluoxetine, naratriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• nilotinib

  nilotinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• omeprazole

  omeprazole will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
  
  fluoxetine will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• panax ginseng

  panax ginseng increases effects of fluoxetine by pharmacodynamic synergism. Minor/Significance Unknown.

• ruxolitinib

  olanzapine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• parecoxib

  parecoxib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• pazopanib

  fluoxetine and pazopanib both increase QTc interval. Minor/Significance Unknown.

• pleurisy root

  pleurisy root decreases effects of fluoxetine by unspecified interaction mechanism. Minor/Significance Unknown. Theoretical interaction.

• quinacrine

  quinacrine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• rabeprazole

  fluoxetine will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• ranolazine

  ranolazine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• ritonavir

  ritonavir will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• rizatriptan

  fluoxetine, rizatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• ruxolitinib

  fluoxetine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ruxolitinib topical

  olanzapine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  fluoxetine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• sage

  olanzapine and sage both increase sedation. Minor/Significance Unknown.

• serdexmethylphenidate/dexmethylphenidate

  serdexmethylphenidate/dexmethylphenidate increases effects of fluoxetine by decreasing metabolism. Minor/Significance Unknown.

• sumatriptan

  fluoxetine, sumatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• 5-HTP

  Monitor Closely (1)fluoxetine and 5-HTP both increase serotonin levels. Modify Therapy/Monitor Closely.

• abametapir

  Serious - Use Alternative (1)abametapir will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP1A2 substrates. If not feasible, avoid use of abametapir.

• abiraterone

  Monitor Closely (1)abiraterone increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

• abobotulinumtoxinA

  Monitor Closely (1)abobotulinumtoxinA increases effects of olanzapine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

• acarbose

  Monitor Closely (1)olanzapine, acarbose. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• aceclofenac

  Monitor Closely (1)fluoxetine, aceclofenac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• acemetacin

  Monitor Closely (1)fluoxetine, acemetacin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• aclidinium

  Monitor Closely (3)aclidinium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  aclidinium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• acrivastine

  Monitor Closely (1)acrivastine and olanzapine both increase sedation. Use Caution/Monitor.

• adagrasib

  Serious - Use Alternative (2)adagrasib, fluoxetine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.
  
  adagrasib, olanzapine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.

• albiglutide

  Monitor Closely (1)olanzapine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• albuterol

  Monitor Closely (3)albuterol and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  albuterol and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• alfentanil

  Monitor Closely (1)alfentanil and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)alfentanil, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• alfuzosin

  Monitor Closely (4)fluoxetine and alfuzosin both increase QTc interval. Use Caution/Monitor.
  
  alfuzosin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and alfuzosin both increase QTc interval. Use Caution/Monitor.
  
  alfuzosin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• almotriptan

  Monitor Closely (2)almotriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  almotriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Minor (1)fluoxetine, almotriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• alosetron

  Monitor Closely (1)fluoxetine will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• alpelisib

  Monitor Closely (1)alpelisib will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• alprazolam

  Monitor Closely (1)alprazolam and olanzapine both increase sedation. Use Caution/Monitor.

• amifampridine

  Monitor Closely (1)fluoxetine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amifostine

  Monitor Closely (1)amifostine, olanzapine. Either increases effects of the other by anti-hypertensive channel blocking. Use Caution/Monitor. Due to its alpha adrenergic antagonism, atypical antipsychotic agents has the potential to enhance the effect of certain antihypertensive agents. Monitor blood pressure and adjust dose accordingly.

• amiodarone

  Monitor Closely (1)amiodarone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)olanzapine and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.
  
  amiodarone and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• amisulpride

  Contraindicated (1)amisulpride, olanzapine. Either increases toxicity of the other by Other (see comment). Contraindicated. Comment: Increases risk of neuroleptic malignant syndromeIncreases risk of neuroleptic malignant syndrome.Serious - Use Alternative (2)amisulpride and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  amisulpride and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.

• amitriptyline

  Monitor Closely (3)olanzapine and amitriptyline both increase QTc interval. Use Caution/Monitor.
  
  amitriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and amitriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug.

• amobarbital

  Monitor Closely (2)amobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  amobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• amoxapine

  Monitor Closely (4)olanzapine and amoxapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  amoxapine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and amoxapine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine and amoxapine both increase serotonin levels. Avoid or Use Alternate Drug.

• anagrelide

  Serious - Use Alternative (2)anagrelide and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and anagrelide both increase QTc interval. Avoid or Use Alternate Drug.

• anticholinergic/sedative combos

  Monitor Closely (3)anticholinergic/sedative combos decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  anticholinergic/sedative combos decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• apalutamide

  Monitor Closely (1)apalutamide will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Coadministration of apalutamide, a weak CYP2C9 inducer, with drugs that are CYP2C9 substrates can result in lower exposure to these medications. Evaluate for loss of therapeutic effect if medication must be coadministered.

• apixaban

  Monitor Closely (1)fluoxetine increases effects of apixaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• apomorphine

  Monitor Closely (2)apomorphine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and apomorphine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)olanzapine decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.
  
  apomorphine and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• arformoterol

  Monitor Closely (3)arformoterol and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  arformoterol and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  olanzapine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• aripiprazole

  Monitor Closely (3)aripiprazole and olanzapine both increase sedation. Use Caution/Monitor.
  
  aripiprazole and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  aripiprazole and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesSerious - Use Alternative (2)fluoxetine will increase the level or effect of aripiprazole by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  aripiprazole and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• armodafinil

  Monitor Closely (2)armodafinil will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  olanzapine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• arsenic trioxide

  Serious - Use Alternative (2)arsenic trioxide and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and arsenic trioxide both increase QTc interval. Avoid or Use Alternate Drug.

• artemether

  Serious - Use Alternative (2)artemether and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  artemether and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• artemether/lumefantrine

  Contraindicated (1)artemether/lumefantrine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.Monitor Closely (1)fluoxetine and artemether/lumefantrine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)olanzapine and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine

  Monitor Closely (3)asenapine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  asenapine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  asenapine and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and asenapine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine transdermal

  Monitor Closely (3)asenapine transdermal and olanzapine both increase sedation. Use Caution/Monitor.
  
  asenapine transdermal and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  asenapine transdermal and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• aspirin

  Monitor Closely (1)fluoxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• aspirin rectal

  Monitor Closely (1)fluoxetine, aspirin rectal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• aspirin/citric acid/sodium bicarbonate

  Monitor Closely (1)fluoxetine, aspirin/citric acid/sodium bicarbonate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• atogepant

  Monitor Closely (1)fluoxetine will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atomoxetine

  Monitor Closely (2)fluoxetine will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Reduced initial doses of atomoxetine are recommended with strong CYP2D6 inhibitors.
  
  atomoxetine and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesSerious - Use Alternative (1)atomoxetine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• atracurium

  Monitor Closely (3)atracurium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atracurium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• atropine

  Monitor Closely (3)atropine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• atropine IV/IM

  Monitor Closely (3)olanzapine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  atropine IV/IM decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine IV/IM decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.

• avapritinib

  Monitor Closely (3)avapritinib and olanzapine both increase sedation. Use Caution/Monitor.
  
  olanzapine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• axitinib

  Monitor Closely (2)fluoxetine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  olanzapine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• azelastine

  Monitor Closely (1)azelastine and olanzapine both increase sedation. Use Caution/Monitor.

• azithromycin

  Monitor Closely (1)azithromycin increases toxicity of olanzapine by QTc interval. Use Caution/Monitor.Minor (1)azithromycin and fluoxetine both increase QTc interval. Minor/Significance Unknown.

• baclofen

  Monitor Closely (1)baclofen and olanzapine both increase sedation. Use Caution/Monitor.

• bedaquiline

  Monitor Closely (2)fluoxetine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely
  
  olanzapine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely

• belladonna alkaloids

  Monitor Closely (3)belladonna alkaloids decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  belladonna alkaloids decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of belladonna alkaloids by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• belladonna and opium

  Monitor Closely (4)belladonna and opium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  belladonna and opium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  belladonna and opium and olanzapine both increase sedation. Use Caution/Monitor.

• benazepril

  Monitor Closely (1)olanzapine, benazepril. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Enhanced hypotensive effects.

• benperidol

  Monitor Closely (2)benperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  benperidol and olanzapine both increase sedation. Use Caution/Monitor.

• benzhydrocodone/acetaminophen

  Monitor Closely (2)benzhydrocodone/acetaminophen, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.
  
  benzhydrocodone/acetaminophen and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)benzhydrocodone/acetaminophen, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• benzphetamine

  Monitor Closely (1)olanzapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• benztropine

  Monitor Closely (1)olanzapine increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .

• betrixaban

  Monitor Closely (1)fluoxetine increases effects of betrixaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• bosentan

  Monitor Closely (1)fluoxetine will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• brexanolone

  Monitor Closely (1)brexanolone, olanzapine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brexpiprazole

  Monitor Closely (2)fluoxetine will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP2D6 inhibitors. If also administered with a strong/moderate CYP3A4 inhibitor, administer a quarter of brexpiprazole dose. NOTE: In MDD clinical trials, brexpiprazole dosage was not adjusted for strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine); thus, CYP considerations are already factored into general dosing recommendations and brexpiprazole may be administered without dosage adjustment in patients with MDD.
  
  brexpiprazole and olanzapine both increase sedation. Use Caution/Monitor.

• brimonidine

  Monitor Closely (1)brimonidine and olanzapine both increase sedation. Use Caution/Monitor.Minor (1)brimonidine increases effects of olanzapine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

• brivaracetam

  Monitor Closely (1)brivaracetam and olanzapine both increase sedation. Use Caution/Monitor.

• bromocriptine

  Serious - Use Alternative (1)olanzapine decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• brompheniramine

  Monitor Closely (1)brompheniramine and olanzapine both increase sedation. Use Caution/Monitor.

• bumetanide

  Minor (1)bumetanide, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• buprenorphine

  Monitor Closely (1)buprenorphine and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)olanzapine and buprenorphine both increase QTc interval. Avoid or Use Alternate Drug. If concurrent use of olanzapine and buprenorphine is necessary, consider dose reduction of one or both drugs.
  
  buprenorphine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine buccal

  Monitor Closely (1)buprenorphine buccal and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)buprenorphine buccal and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine buccal and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• buprenorphine subdermal implant

  Monitor Closely (2)buprenorphine subdermal implant and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine, buprenorphine subdermal implant. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.Serious - Use Alternative (2)buprenorphine subdermal implant and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine subdermal implant and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• buprenorphine transdermal

  Serious - Use Alternative (2)buprenorphine transdermal and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine transdermal and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• buprenorphine, long-acting injection

  Monitor Closely (2)olanzapine increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.
  
  fluoxetine, buprenorphine, long-acting injection. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.Serious - Use Alternative (2)buprenorphine, long-acting injection and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  buprenorphine, long-acting injection and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• bupropion

  Monitor Closely (1)bupropion will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine increases toxicity of bupropion by unspecified interaction mechanism. Avoid or Use Alternate Drug. May lower seizure threshold; keep bupropion dose as low as possible.

• buspirone

  Serious - Use Alternative (1)fluoxetine and buspirone both increase serotonin levels. Avoid or Use Alternate Drug.

• butabarbital

  Monitor Closely (2)butabarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  butabarbital and olanzapine both increase sedation. Use Caution/Monitor.

• butalbital

  Monitor Closely (2)butalbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  butalbital and olanzapine both increase sedation. Use Caution/Monitor.

• butorphanol

  Monitor Closely (1)butorphanol and olanzapine both increase sedation. Use Caution/Monitor.

• cabergoline

  Serious - Use Alternative (1)olanzapine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

• caffeine

  Monitor Closely (1)olanzapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• calcium/magnesium/potassium/sodium oxybates

  Serious - Use Alternative (1)olanzapine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• cannabidiol

  Monitor Closely (3)fluoxetine will increase the level or effect of cannabidiol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP2C19 inhibitor.
  
  cannabidiol, olanzapine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP1A2 induction and inhibition with the coadministration of CYP1A2 substrates and cannabidiol, consider reducing dosage adjustment of CYP1A2 substrates as clinically appropriate.
  
  cannabidiol will increase the level or effect of fluoxetine by decreasing metabolism. Modify Therapy/Monitor Closely. Cannabidiol may potentially inhibit CYP2C9 activity. Consider reducing the dose when concomitantly using CYP2C9 substrates.

• captopril

  Monitor Closely (1)olanzapine, captopril. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure. Monitor blood pressure.

• carbamazepine

  Monitor Closely (2)fluoxetine will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor plasma levels when used concomitantly
  
  carbamazepine will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• carbinoxamine

  Monitor Closely (1)carbinoxamine and olanzapine both increase sedation. Use Caution/Monitor.

• carisoprodol

  Monitor Closely (1)carisoprodol and olanzapine both increase sedation. Use Caution/Monitor.

• carvedilol

  Monitor Closely (1)fluoxetine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• celandine

  Minor (1)celandine decreases effects of fluoxetine by pharmacodynamic antagonism. Minor/Significance Unknown. Based on animal studies.

• celecoxib

  Monitor Closely (3)fluoxetine will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  celecoxib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine, celecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ceritinib

  Serious - Use Alternative (2)ceritinib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  ceritinib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• chasteberry

  Minor (1)chasteberry decreases effects of olanzapine by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).

• chloral hydrate

  Monitor Closely (1)chloral hydrate and olanzapine both increase sedation. Use Caution/Monitor.

• chlordiazepoxide

  Monitor Closely (1)chlordiazepoxide and olanzapine both increase sedation. Use Caution/Monitor.

• chloroquine

  Monitor Closely (1)chloroquine increases toxicity of olanzapine by QTc interval. Use Caution/Monitor.Minor (2)chloroquine increases toxicity of fluoxetine by QTc interval. Minor/Significance Unknown.
  
  chloroquine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• chlorpheniramine

  Monitor Closely (1)chlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.

• chlorpromazine

  Monitor Closely (3)chlorpromazine and olanzapine both increase sedation. Use Caution/Monitor.
  
  chlorpromazine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  chlorpromazine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (2)olanzapine and chlorpromazine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• chlorpropamide

  Monitor Closely (2)fluoxetine increases effects of chlorpropamide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, chlorpropamide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• chlorzoxazone

  Monitor Closely (1)chlorzoxazone and olanzapine both increase sedation. Use Caution/Monitor.

• choline magnesium trisalicylate

  Monitor Closely (1)fluoxetine, choline magnesium trisalicylate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• cigarette smoking

  Monitor Closely (1)cigarette smoking will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• cilostazol

  Monitor Closely (1)fluoxetine increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider decreasing cilostazol dose; moderate CYP2C19 inhibitors may increase serum levels of 3,4-dehydrocilostazol (active metabolite).

• cimetidine

  Monitor Closely (2)cimetidine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  cimetidine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• cinnarizine

  Monitor Closely (1)cinnarizine and olanzapine both increase sedation. Use Caution/Monitor.

• ciprofloxacin

  Monitor Closely (2)ciprofloxacin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  ciprofloxacin will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Olanzapine plasma concentrations may be elevated, increasing the risk of adverse reactions such as orthostatic hypotension or sedation. It is important to use caution and observe patient and adjust the olanzapine dosage as needed.Serious - Use Alternative (1)olanzapine and ciprofloxacin both increase QTc interval. Avoid or Use Alternate Drug.

• cisatracurium

  Monitor Closely (3)cisatracurium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cisatracurium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• citalopram

  Monitor Closely (1)citalopram and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)citalopram and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  citalopram and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

• clarithromycin

  Monitor Closely (1)clarithromycin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)clarithromycin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• clemastine

  Monitor Closely (1)clemastine and olanzapine both increase sedation. Use Caution/Monitor.

• clobazam

  Monitor Closely (2)olanzapine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
  
  clobazam will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.

• clomipramine

  Monitor Closely (3)olanzapine and clomipramine both increase sedation. Use Caution/Monitor.
  
  clomipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and clomipramine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine and clomipramine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• clonazepam

  Monitor Closely (1)clonazepam and olanzapine both increase sedation. Use Caution/Monitor.

• clonidine

  Monitor Closely (2)clonidine, fluoxetine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration enhances CNS depressant effects.
  
  clonidine, olanzapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

• clopidogrel

  Monitor Closely (1)fluoxetine increases effects of clopidogrel by pharmacodynamic synergism. Use Caution/Monitor. SSRIs affect platelet activation; coadministration of SSRIs with clopidogrel may increase the risk of bleeding.Serious - Use Alternative (1)fluoxetine decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .

• clorazepate

  Monitor Closely (1)clorazepate and olanzapine both increase sedation. Use Caution/Monitor.

• clozapine

  Monitor Closely (4)fluoxetine increases levels of clozapine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Plasma levels of clozapine may be increased, resulting in increased pharmacologic and toxic effects. Adjust clozapine dose as needed when initiating or discontinuing certain SSRIs. .
  
  clozapine and olanzapine both increase sedation. Use Caution/Monitor.
  
  clozapine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  clozapine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)clozapine and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• cobicistat

  Monitor Closely (1)cobicistat will increase the level or effect of fluoxetine by Other (see comment). Use Caution/Monitor. Carefully titrate dose of the antidepressant to the desired effect, including using the lowest feasible initial or maintenance dose, and monitor its response during coadministration with SSRIs and cobicistat.

• cocaine topical

  Monitor Closely (1)fluoxetine and cocaine topical both increase serotonin levels. Modify Therapy/Monitor Closely.

• codeine

  Monitor Closely (2)codeine and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphineMinor (1)fluoxetine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• crizotinib

  Monitor Closely (1)crizotinib and fluoxetine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended, along with drugs that may prolong the QT interval.Serious - Use Alternative (1)crizotinib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• cyclizine

  Monitor Closely (4)cyclizine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cyclizine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of cyclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  cyclizine and olanzapine both increase sedation. Use Caution/Monitor.

• cyclobenzaprine

  Monitor Closely (4)olanzapine increases effects of cyclobenzaprine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  cyclobenzaprine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cyclobenzaprine and olanzapine both increase sedation. Use Caution/Monitor.
  
  cyclobenzaprine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine and cyclobenzaprine both increase serotonin levels. Avoid or Use Alternate Drug.

• cyproheptadine

  Monitor Closely (2)cyproheptadine decreases effects of fluoxetine by pharmacodynamic antagonism. Use Caution/Monitor. Cyproheptadine may diminish the serotonergic effect of SSRIs.
  
  cyproheptadine and olanzapine both increase sedation. Use Caution/Monitor.

• dacomitinib

  Serious - Use Alternative (1)dacomitinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.

• dantrolene

  Monitor Closely (1)dantrolene and olanzapine both increase sedation. Use Caution/Monitor.

• daridorexant

  Monitor Closely (2)fluoxetine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
  
  olanzapine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• darifenacin

  Monitor Closely (3)olanzapine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  darifenacin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  darifenacin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.Minor (1)darifenacin will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• darunavir

  Monitor Closely (1)darunavir will increase the level or effect of fluoxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with SSRIs, TCAs, or trazodone may require dose titration of antidepressant to desired effect (eg, using the lowest feasible initial or maintenance dose). Monitor for antidepressant response.

• dasatinib

  Monitor Closely (2)dasatinib and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  dasatinib and fluoxetine both increase QTc interval. Use Caution/Monitor.

• deferasirox

  Monitor Closely (1)deferasirox will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• defibrotide

  Monitor Closely (1)defibrotide increases effects of fluoxetine by Other (see comment). Use Caution/Monitor. Comment: Defibrotide may enhance effects of platelet inhibitors.

• degarelix

  Monitor Closely (1)degarelix and fluoxetine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)degarelix and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• desflurane

  Serious - Use Alternative (2)desflurane and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  desflurane and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• desipramine

  Monitor Closely (3)olanzapine and desipramine both increase sedation. Use Caution/Monitor.
  
  olanzapine and desipramine both increase QTc interval. Use Caution/Monitor.
  
  desipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)fluoxetine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and desipramine both increase serotonin levels. Avoid or Use Alternate Drug.

• desvenlafaxine

  Monitor Closely (1)desvenlafaxine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mgSerious - Use Alternative (1)fluoxetine and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.

• deutetrabenazine

  Monitor Closely (5)deutetrabenazine and olanzapine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).
  
  fluoxetine will increase the level or effect of deutetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Strong CYP2D6 inhibitors increase the systemic exposure to the active dihydro-metabolites of deutetrabenazine by approximately 3-fold. Do not exceed 18 mg/dose and 36 mg/day of deutetrabenazine if coadministered with strong CYP2D6 inhibitors.
  
  olanzapine and deutetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely. The risk for parkinsonism, neuroleptic malignant syndrome, and akathisia may be increased by concomitant use of deutetrabenazine and dopamine antagonists or antipsychotics.
  
  deutetrabenazine and fluoxetine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).
  
  olanzapine and deutetrabenazine both increase sedation. Use Caution/Monitor.

• dexchlorpheniramine

  Monitor Closely (1)dexchlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.

• dexfenfluramine

  Monitor Closely (3)fluoxetine will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine and dexfenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  olanzapine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dexmedetomidine

  Monitor Closely (1)dexmedetomidine and olanzapine both increase sedation. Use Caution/Monitor.

• dexmethylphenidate

  Monitor Closely (1)olanzapine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)dexmethylphenidate increases effects of fluoxetine by decreasing metabolism. Minor/Significance Unknown.

• dextroamphetamine

  Monitor Closely (3)fluoxetine and dextroamphetamine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  olanzapine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• dextroamphetamine transdermal

  Monitor Closely (2)fluoxetine, dextroamphetamine transdermal. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and concomitant serotonergic drug(s).
  
  fluoxetine will increase the level or effect of dextroamphetamine transdermal by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome, particularly during dextroamphetamine initiation and after a dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and CYP2D6 inhibitor.

• dextromethorphan

  Monitor Closely (1)dextromethorphan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (2)fluoxetine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• dextromoramide

  Monitor Closely (1)dextromoramide and olanzapine both increase sedation. Use Caution/Monitor.

• diamorphine

  Monitor Closely (1)diamorphine and olanzapine both increase sedation. Use Caution/Monitor.

• diazepam

  Monitor Closely (2)fluoxetine will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  diazepam and olanzapine both increase sedation. Use Caution/Monitor.

• diazepam intranasal

  Monitor Closely (2)fluoxetine will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
  
  diazepam intranasal, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.

• dichlorphenamide

  Monitor Closely (1)dichlorphenamide and fluoxetine both decrease serum potassium. Use Caution/Monitor.

• diclofenac

  Monitor Closely (2)fluoxetine will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, diclofenac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• dicyclomine

  Monitor Closely (3)dicyclomine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  dicyclomine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• diethylpropion

  Monitor Closely (1)olanzapine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• difelikefalin

  Monitor Closely (2)difelikefalin and olanzapine both increase sedation. Use Caution/Monitor.
  
  difelikefalin and fluoxetine both increase sedation. Use Caution/Monitor.

• difenoxin hcl

  Monitor Closely (1)difenoxin hcl and olanzapine both increase sedation. Use Caution/Monitor.

• diflunisal

  Monitor Closely (1)fluoxetine, diflunisal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• dihydroergotamine

  Monitor Closely (2)dihydroergotamine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and dihydroergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.

• dihydroergotamine intranasal

  Monitor Closely (1)fluoxetine and dihydroergotamine intranasal both increase serotonin levels. Modify Therapy/Monitor Closely.

• dimenhydrinate

  Monitor Closely (1)dimenhydrinate and olanzapine both increase sedation. Use Caution/Monitor.

• diphenhydramine

  Monitor Closely (4)diphenhydramine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  diphenhydramine and olanzapine both increase sedation. Use Caution/Monitor.
  
  diphenhydramine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  olanzapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)diphenhydramine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• diphenoxylate hcl

  Monitor Closely (1)diphenoxylate hcl and olanzapine both increase sedation. Use Caution/Monitor.

• dipipanone

  Monitor Closely (1)dipipanone and olanzapine both increase sedation. Use Caution/Monitor.

• disopyramide

  Serious - Use Alternative (2)olanzapine and disopyramide both increase QTc interval. Avoid or Use Alternate Drug.
  
  disopyramide and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• dobutamine

  Monitor Closely (1)olanzapine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dofetilide

  Monitor Closely (2)dofetilide increases toxicity of olanzapine by QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.
  
  dofetilide and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• dolasetron

  Monitor Closely (2)dolasetron and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  dolasetron and olanzapine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)dolasetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• donepezil

  Monitor Closely (3)donepezil and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  fluoxetine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  donepezil and fluoxetine both increase QTc interval. Use Caution/Monitor.

• dopamine

  Monitor Closely (1)olanzapine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

• dopexamine

  Monitor Closely (1)olanzapine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dosulepin

  Monitor Closely (1)olanzapine and dosulepin both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine and dosulepin both increase serotonin levels. Avoid or Use Alternate Drug.

• doxepin

  Monitor Closely (3)doxepin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and doxepin both increase sedation. Use Caution/Monitor.
  
  doxepin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesSerious - Use Alternative (2)fluoxetine and doxepin both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• doxylamine

  Monitor Closely (1)doxylamine and olanzapine both increase sedation. Use Caution/Monitor.

• dronedarone

  Contraindicated (1)olanzapine and dronedarone both increase QTc interval. Contraindicated.Monitor Closely (1)dronedarone and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)dronedarone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• droperidol

  Monitor Closely (3)droperidol and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  droperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  droperidol and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and droperidol both increase QTc interval. Avoid or Use Alternate Drug.

• duloxetine

  Serious - Use Alternative (2)duloxetine and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.Minor (1)duloxetine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• edoxaban

  Monitor Closely (1)fluoxetine increases effects of edoxaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• efavirenz

  Monitor Closely (2)efavirenz and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  efavirenz and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• eletriptan

  Monitor Closely (2)eletriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  eletriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)fluoxetine, eletriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• eliglustat

  Contraindicated (1)fluoxetine increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.Monitor Closely (1)eliglustat increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.Serious - Use Alternative (2)eliglustat and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and eliglustat both increase QTc interval. Avoid or Use Alternate Drug.

• eluxadoline

  Monitor Closely (1)fluoxetine increases levels of eluxadoline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2D6 inhibitors.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Monitor Closely (2)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
  
  elvitegravir/cobicistat/emtricitabine/tenofovir DF decreases levels of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Elvitegravir is a moderate CYP2C9 inducer.

• encainide

  Monitor Closely (1)fluoxetine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• encorafenib

  Serious - Use Alternative (2)encorafenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Encorafenib is associated with dose-dependent QTc interval prolongation. Avoid with drugs known to prolong QT interval.
  
  encorafenib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• entrectinib

  Serious - Use Alternative (2)fluoxetine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.

• ephedrine

  Monitor Closely (1)olanzapine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine

  Monitor Closely (2)olanzapine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  epinephrine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• epinephrine racemic

  Monitor Closely (2)olanzapine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  epinephrine racemic and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• erdafitinib

  Serious - Use Alternative (1)olanzapine will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

• ergoloid mesylates

  Monitor Closely (1)ergoloid mesylates, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• ergotamine

  Monitor Closely (2)ergotamine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and ergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.

• eribulin

  Monitor Closely (1)eribulin and fluoxetine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)eribulin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• erythromycin base

  Monitor Closely (2)erythromycin base and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  erythromycin base will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Monitor Closely (2)erythromycin ethylsuccinate and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  erythromycin ethylsuccinate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Monitor Closely (2)erythromycin lactobionate and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  erythromycin lactobionate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin stearate

  Monitor Closely (2)erythromycin stearate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  erythromycin stearate and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)olanzapine and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.

• escitalopram

  Monitor Closely (2)escitalopram increases toxicity of olanzapine by QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.
  
  escitalopram and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)escitalopram and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• esketamine intranasal

  Monitor Closely (1)esketamine intranasal, olanzapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• esomeprazole

  Minor (1)fluoxetine will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• estazolam

  Monitor Closely (1)estazolam and olanzapine both increase sedation. Use Caution/Monitor.

• ethacrynic acid

  Minor (1)ethacrynic acid, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• ethanol

  Monitor Closely (1)olanzapine and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.

• ethinylestradiol

  Monitor Closely (1)ethinylestradiol will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• ethotoin

  Monitor Closely (1)fluoxetine will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• etodolac

  Monitor Closely (1)fluoxetine, etodolac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• etravirine

  Monitor Closely (1)fluoxetine will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• eucalyptus

  Minor (1)olanzapine and eucalyptus both increase sedation. Minor/Significance Unknown.

• exenatide injectable solution

  Monitor Closely (1)olanzapine, exenatide injectable solution. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• exenatide injectable suspension

  Monitor Closely (1)olanzapine, exenatide injectable suspension. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• ezogabine

  Monitor Closely (1)ezogabine and fluoxetine both increase QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.

• fedratinib

  Monitor Closely (1)fedratinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.Serious - Use Alternative (2)fluoxetine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
  
  olanzapine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

• fenbufen

  Monitor Closely (1)fluoxetine, fenbufen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• fenfluramine

  Monitor Closely (4)olanzapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
  
  fenfluramine, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
  
  olanzapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.

• fenoprofen

  Monitor Closely (1)fluoxetine, fenoprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• fentanyl

  Monitor Closely (1)fentanyl, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fentanyl, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fentanyl intranasal

  Serious - Use Alternative (1)fentanyl intranasal, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fentanyl transdermal

  Serious - Use Alternative (1)fentanyl transdermal, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fentanyl transmucosal

  Serious - Use Alternative (1)fentanyl transmucosal, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• fesoterodine

  Monitor Closely (4)fesoterodine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fesoterodine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  olanzapine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• fexinidazole

  Monitor Closely (1)fexinidazole will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)fexinidazole and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.
  
  fexinidazole and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.

• fezolinetant

  Contraindicated (2)fluoxetine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors
  
  olanzapine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

• finerenone

  Monitor Closely (2)olanzapine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.
  
  fluoxetine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

• fingolimod

  Monitor Closely (2)fingolimod and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  fingolimod and fluoxetine both increase QTc interval. Use Caution/Monitor.

• fish oil triglycerides

  Monitor Closely (1)fish oil triglycerides will increase the level or effect of fluoxetine by anticoagulation. Use Caution/Monitor. Prolonged bleeding reported in patients taking antiplatelet agents or anticoagulants and oral omega-3 fatty acids. Periodically monitor bleeding time in patients receiving fish oil triglycerides and concomitant antiplatelet agents or anticoagulants.

• flavoxate

  Monitor Closely (3)flavoxate decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  flavoxate decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• flecainide

  Monitor Closely (2)olanzapine and flecainide both increase QTc interval. Use Caution/Monitor.
  
  flecainide and fluoxetine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• flibanserin

  Monitor Closely (3)flibanserin, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  olanzapine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.
  
  fluoxetine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

• fluconazole

  Monitor Closely (2)olanzapine and fluconazole both increase QTc interval. Use Caution/Monitor.
  
  fluconazole and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• fluoxetine

  Monitor Closely (1)olanzapine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• fluphenazine

  Monitor Closely (3)olanzapine and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  fluphenazine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)fluphenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• flurazepam

  Monitor Closely (1)flurazepam and olanzapine both increase sedation. Use Caution/Monitor.

• flurbiprofen

  Monitor Closely (2)fluoxetine will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, flurbiprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• fluvastatin

  Monitor Closely (1)fluoxetine will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fluvoxamine

  Serious - Use Alternative (3)fluvoxamine and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  olanzapine and fluvoxamine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluvoxamine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

• fondaparinux

  Monitor Closely (1)fluoxetine increases effects of fondaparinux by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.

• formoterol

  Monitor Closely (2)fluoxetine and formoterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system
  
  olanzapine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• foscarnet

  Monitor Closely (1)fluoxetine and foscarnet both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

• fosphenytoin

  Monitor Closely (1)fluoxetine will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fostemsavir

  Monitor Closely (2)olanzapine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.
  
  fluoxetine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

• frovatriptan

  Monitor Closely (2)frovatriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  frovatriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Minor (1)fluoxetine, frovatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• furosemide

  Minor (1)furosemide, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• gabapentin

  Monitor Closely (1)gabapentin, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• gabapentin enacarbil

  Monitor Closely (1)gabapentin enacarbil, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• gadobenate

  Monitor Closely (1)gadobenate and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• galantamine

  Monitor Closely (1)fluoxetine will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• ganaxolone

  Monitor Closely (2)olanzapine and ganaxolone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and ganaxolone both increase sedation. Use Caution/Monitor.

• gemifloxacin

  Monitor Closely (2)gemifloxacin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  gemifloxacin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• gemtuzumab

  Monitor Closely (1)olanzapine and gemtuzumab both increase QTc interval. Use Caution/Monitor.

• gilteritinib

  Monitor Closely (1)gilteritinib and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesSerious - Use Alternative (2)gilteritinib will decrease the level or effect of fluoxetine by Other (see comment). Avoid or Use Alternate Drug. Coadministration of gilteritinib with drugs that inhibit 5HT2B or sigma nonspecific receptors. Avoid use of these drugs with gilteritinib unless coadministration is necessary.
  
  gilteritinib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• givosiran

  Serious - Use Alternative (2)givosiran will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP1A2 substrates with givosiran. If unavoidable, decrease the CYP1A2 substrate dosage in accordance with approved product labeling.
  
  givosiran will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.

• glasdegib

  Serious - Use Alternative (2)olanzapine and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.
  
  fluoxetine and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.

• glimepiride

  Monitor Closely (2)fluoxetine increases effects of glimepiride by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, glimepiride. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• glipizide

  Monitor Closely (2)fluoxetine increases effects of glipizide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, glipizide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• glyburide

  Monitor Closely (2)fluoxetine increases effects of glyburide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, glyburide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• glycopyrrolate

  Monitor Closely (1)olanzapine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• glycopyrrolate inhaled

  Monitor Closely (3)glycopyrrolate inhaled decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  glycopyrrolate inhaled decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• goserelin

  Contraindicated (1)goserelin increases toxicity of fluoxetine by QTc interval. Contraindicated. Increases risk of torsades de pointes.Serious - Use Alternative (1)olanzapine and goserelin both increase QTc interval. Avoid or Use Alternate Drug.

• granisetron

  Monitor Closely (2)granisetron and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  granisetron and fluoxetine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)granisetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• green tea

  Monitor Closely (1)green tea, fluoxetine. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of bleeding.

• guanfacine

  Monitor Closely (1)guanfacine, olanzapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

• haloperidol

  Monitor Closely (4)haloperidol and olanzapine both increase sedation. Use Caution/Monitor.
  
  haloperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluoxetine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.
  
  haloperidol and olanzapine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  haloperidol will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• henbane

  Monitor Closely (3)henbane decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  henbane decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• histrelin

  Serious - Use Alternative (2)olanzapine and histrelin both increase QTc interval. Avoid or Use Alternate Drug.
  
  histrelin increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• homatropine

  Monitor Closely (3)homatropine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  homatropine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hydrocodone

  Monitor Closely (1)hydrocodone, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.Serious - Use Alternative (1)hydrocodone, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• hydromorphone

  Monitor Closely (1)hydromorphone and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  hydromorphone, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• hydroxychloroquine sulfate

  Serious - Use Alternative (2)hydroxychloroquine sulfate and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  hydroxychloroquine sulfate and olanzapine both increase QTc interval. Avoid or Use Alternate Drug.

• hydroxyzine

  Monitor Closely (2)hydroxyzine and olanzapine both increase sedation. Use Caution/Monitor.
  
  hydroxyzine and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesSerious - Use Alternative (1)hydroxyzine increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• hyoscyamine

  Monitor Closely (3)hyoscyamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  hyoscyamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hyoscyamine spray

  Monitor Closely (3)olanzapine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  hyoscyamine spray decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  hyoscyamine spray decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.

• ibrutinib

  Monitor Closely (1)ibrutinib will increase the level or effect of fluoxetine by anticoagulation. Use Caution/Monitor. Ibrutinib may increase the risk of hemorrhage in patients receiving antiplatelet or anticoagulant therapies and monitor for signs of bleeding.

• ibuprofen

  Monitor Closely (2)fluoxetine will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, ibuprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ibuprofen IV

  Monitor Closely (2)fluoxetine will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, ibuprofen IV. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ibutilide

  Serious - Use Alternative (2)fluoxetine and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.

• iloperidone

  Monitor Closely (3)fluoxetine and iloperidone both increase QTc interval. Use Caution/Monitor.
  
  iloperidone and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  iloperidone and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  olanzapine and iloperidone both increase QTc interval. Avoid or Use Alternate Drug.

• imatinib

  Monitor Closely (1)imatinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• imipramine

  Monitor Closely (3)olanzapine and imipramine both increase sedation. Use Caution/Monitor.
  
  imipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and imipramine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (3)fluoxetine and imipramine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• incobotulinumtoxinA

  Monitor Closely (1)olanzapine increases effects of incobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• indacaterol, inhaled

  Monitor Closely (1)indacaterol, inhaled and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• indapamide

  Serious - Use Alternative (1)fluoxetine and indapamide both increase QTc interval. Avoid or Use Alternate Drug.

• indomethacin

  Monitor Closely (1)fluoxetine, indomethacin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• inotuzumab

  Serious - Use Alternative (1)olanzapine and inotuzumab both increase QTc interval. Avoid or Use Alternate Drug.

• insulin aspart

  Monitor Closely (2)fluoxetine increases effects of insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.
  
  olanzapine, insulin aspart. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• insulin aspart protamine/insulin aspart

  Monitor Closely (1)fluoxetine increases effects of insulin aspart protamine/insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  Monitor Closely (3)olanzapine decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.
  
  fluoxetine increases effects of insulin degludec by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.
  
  fluoxetine, insulin degludec. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin degludec/insulin aspart

  Monitor Closely (2)fluoxetine, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  olanzapine decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.

• insulin detemir

  Monitor Closely (2)olanzapine, insulin detemir. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin detemir by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin glargine

  Monitor Closely (2)olanzapine, insulin glargine. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin glargine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin glulisine

  Monitor Closely (2)olanzapine, insulin glulisine. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin glulisine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin inhaled

  Monitor Closely (3)olanzapine decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.
  
  fluoxetine, insulin inhaled. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  fluoxetine increases effects of insulin inhaled by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin isophane human/insulin regular human

  Monitor Closely (1)fluoxetine increases effects of insulin isophane human/insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro

  Monitor Closely (2)olanzapine, insulin lispro. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro protamine/insulin lispro

  Monitor Closely (1)fluoxetine increases effects of insulin lispro protamine/insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  Monitor Closely (1)fluoxetine increases effects of insulin NPH by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• insulin regular human

  Monitor Closely (2)olanzapine, insulin regular human. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and fluoxetine may require insulin dosage adjustment and increased glucose monitoring.

• ipratropium

  Monitor Closely (3)ipratropium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  ipratropium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• isavuconazonium sulfate

  Monitor Closely (2)fluoxetine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  olanzapine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isocarboxazid

  Contraindicated (1)isocarboxazid and fluoxetine both increase serotonin levels. Contraindicated.

• isoflurane

  Serious - Use Alternative (2)isoflurane and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  isoflurane and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• isoniazid

  Monitor Closely (2)fluoxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• isoproterenol

  Monitor Closely (1)olanzapine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• isradipine

  Monitor Closely (1)olanzapine and isradipine both increase QTc interval. Use Caution/Monitor.

• itraconazole

  Monitor Closely (2)itraconazole and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  itraconazole and fluoxetine both increase QTc interval. Use Caution/Monitor.

• ivacaftor

  Monitor Closely (2)fluoxetine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .
  
  olanzapine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

• ivosidenib

  Serious - Use Alternative (3)ivosidenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.
  
  ivosidenib will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2C9 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.
  
  ivosidenib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.

• ketoconazole

  Monitor Closely (1)fluoxetine and ketoconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• ketoprofen

  Monitor Closely (1)fluoxetine, ketoprofen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ketorolac

  Monitor Closely (1)fluoxetine, ketorolac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ketorolac intranasal

  Monitor Closely (1)fluoxetine, ketorolac intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• ketotifen, ophthalmic

  Monitor Closely (1)olanzapine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

• L-tryptophan

  Monitor Closely (1)fluoxetine and L-tryptophan both increase serotonin levels. Modify Therapy/Monitor Closely.

• lamotrigine

  Monitor Closely (1)lamotrigine increases toxicity of fluoxetine by unspecified interaction mechanism. Modify Therapy/Monitor Closely. CNS depressants may increase the toxic effects of selective serotonin reuptake inhibitors; psychomotor impairment may be enhanced.

• lansoprazole

  Minor (1)fluoxetine will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• lapatinib

  Monitor Closely (2)fluoxetine and lapatinib both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and lapatinib both increase QTc interval. Use Caution/Monitor.

• lasmiditan

  Monitor Closely (3)fluoxetine increases effects of lasmiditan by serotonin levels. Use Caution/Monitor. Coadministration may increase risk of serotonin syndrome.
  
  lasmiditan, olanzapine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
  
  lasmiditan, fluoxetine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• lefamulin

  Serious - Use Alternative (2)lefamulin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug.
  
  lefamulin and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• lemborexant

  Monitor Closely (4)lemborexant, olanzapine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
  
  lemborexant, fluoxetine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
  
  olanzapine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.
  
  fluoxetine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

• leniolisib

  Serious - Use Alternative (1)leniolisib will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid leniolisib with CYP1A2 substrates that have a narrow therapeutic index

• lenvatinib

  Monitor Closely (1)fluoxetine and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.Serious - Use Alternative (1)olanzapine and lenvatinib both increase QTc interval. Avoid or Use Alternate Drug.

• leuprolide

  Contraindicated (1)leuprolide increases toxicity of fluoxetine by QTc interval. Contraindicated. Increases risk of torsades de pointes.Serious - Use Alternative (1)olanzapine and leuprolide both increase QTc interval. Avoid or Use Alternate Drug.

• levalbuterol

  Monitor Closely (2)olanzapine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine and levalbuterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• levodopa

  Serious - Use Alternative (1)olanzapine decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• levodopa inhaled

  Serious - Use Alternative (1)olanzapine decreases effects of levodopa inhaled by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Atypical (2nd generation) antipsychotics inhibit dopamine D2 receptors in varying degrees (clozapine and quetiapine are lower risk). .

• levofloxacin

  Monitor Closely (2)olanzapine and levofloxacin both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and levofloxacin both increase QTc interval. Use Caution/Monitor.

• levoketoconazole

  Monitor Closely (1)fluoxetine and levoketoconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• levomilnacipran

  Monitor Closely (1)levomilnacipran, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fluoxetine and levomilnacipran both increase serotonin levels. Avoid or Use Alternate Drug.

• levorphanol

  Monitor Closely (1)levorphanol and olanzapine both increase sedation. Use Caution/Monitor.

• linezolid

  Contraindicated (1)linezolid and fluoxetine both increase serotonin levels. Contraindicated. Linezolid may increase serotonin as a result of MAO-A inhibition. If linezolid must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last linezolid dose or after 5 weeks of monitoring, whichever comes first.Monitor Closely (1)linezolid, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• liraglutide

  Monitor Closely (1)olanzapine, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• lisdexamfetamine

  Monitor Closely (2)fluoxetine, lisdexamfetamine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue along with concomitant serotonergic drug(s).
  
  olanzapine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lisuride

  Serious - Use Alternative (1)olanzapine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

• lithium

  Monitor Closely (4)lithium and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  lithium, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and lithium both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  lithium and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesMinor (1)fluoxetine, lithium. Mechanism: unknown. Minor/Significance Unknown. Risk of neurotoxicity.

• lofepramine

  Monitor Closely (1)olanzapine and lofepramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine and lofepramine both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• lofexidine

  Monitor Closely (4)fluoxetine will increase the level or effect of lofexidine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Concomitant use of lofexidine with strong CYP2D6 inhibitors may increase lofexidine plasma levels. Monitor for symptoms of orthostasis and bradycardia if coadministered with a CYP2D6 inhibitor. Consider lofexidine dose reduction.
  
  fluoxetine and lofexidine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended.
  
  olanzapine and lofexidine both increase sedation. Use Caution/Monitor.
  
  olanzapine and lofexidine both increase QTc interval. Use Caution/Monitor.

• lomitapide

  Monitor Closely (2)olanzapine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.
  
  fluoxetine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

• lonafarnib

  Serious - Use Alternative (2)fluoxetine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.
  
  olanzapine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

• loperamide

  Monitor Closely (1)olanzapine and loperamide both increase QTc interval. Use Caution/Monitor.

• lopinavir

  Serious - Use Alternative (1)olanzapine and lopinavir both increase QTc interval. Avoid or Use Alternate Drug.

• loprazolam

  Monitor Closely (1)loprazolam and olanzapine both increase sedation. Use Caution/Monitor.

• loratadine

  Monitor Closely (1)fluoxetine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• lorazepam

  Monitor Closely (1)lorazepam and olanzapine both increase sedation. Use Caution/Monitor.

• lorcaserin

  Monitor Closely (2)lorcaserin will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  lorcaserin, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fluoxetine and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.

• lormetazepam

  Monitor Closely (1)lormetazepam and olanzapine both increase sedation. Use Caution/Monitor.

• lornoxicam

  Monitor Closely (1)fluoxetine, lornoxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• losartan

  Monitor Closely (1)fluoxetine will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.Minor (1)fluoxetine decreases effects of losartan by decreasing metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• loxapine

  Monitor Closely (2)loxapine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  loxapine and olanzapine both increase sedation. Use Caution/Monitor.

• loxapine inhaled

  Monitor Closely (2)loxapine inhaled and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  loxapine inhaled and olanzapine both increase sedation. Use Caution/Monitor.

• lsd

  Monitor Closely (1)fluoxetine and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.

• lumacaftor/ivacaftor

  Monitor Closely (1)lumacaftor/ivacaftor, fluoxetine. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C9 substrates. .

• lumefantrine

  Contraindicated (1)lumefantrine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.Monitor Closely (1)fluoxetine and lumefantrine both increase QTc interval. Modify Therapy/Monitor Closely.

• lurasidone

  Monitor Closely (2)lurasidone, olanzapine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
  
  lurasidone, fluoxetine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• macimorelin

  Serious - Use Alternative (2)macimorelin and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.
  
  macimorelin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.

• maprotiline

  Monitor Closely (2)maprotiline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and maprotiline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)olanzapine and maprotiline both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine and maprotiline both increase serotonin levels. Avoid or Use Alternate Drug.

• maraviroc

  Monitor Closely (1)maraviroc, olanzapine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.Minor (1)maraviroc will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• marijuana

  Monitor Closely (1)olanzapine and marijuana both increase sedation. Use Caution/Monitor.Minor (1)marijuana will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• mavacamten

  Contraindicated (1)fluoxetine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)olanzapine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• meclizine

  Monitor Closely (3)meclizine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  meclizine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• meclofenamate

  Monitor Closely (1)fluoxetine, meclofenamate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• mefenamic acid

  Monitor Closely (1)fluoxetine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• mefloquine

  Serious - Use Alternative (2)mefloquine increases toxicity of olanzapine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.
  
  mefloquine increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.

• melatonin

  Monitor Closely (1)olanzapine and melatonin both increase sedation. Use Caution/Monitor.

• meloxicam

  Monitor Closely (2)fluoxetine will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, meloxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• meperidine

  Monitor Closely (2)meperidine and olanzapine both increase sedation. Use Caution/Monitor.
  
  meperidine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (2)meperidine, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine and meperidine both increase serotonin levels. Avoid or Use Alternate Drug.

• meprobamate

  Monitor Closely (1)olanzapine and meprobamate both increase sedation. Use Caution/Monitor.

• metaproterenol

  Monitor Closely (1)olanzapine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metaxalone

  Monitor Closely (1)metaxalone and olanzapine both increase sedation. Use Caution/Monitor.

• metformin

  Monitor Closely (2)olanzapine, metformin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine increases effects of metformin by pharmacodynamic synergism. Use Caution/Monitor.

• methadone

  Monitor Closely (3)fluoxetine and methadone both increase QTc interval. Use Caution/Monitor.
  
  methadone and olanzapine both increase sedation. Use Caution/Monitor.
  
  methadone, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)olanzapine and methadone both increase QTc interval. Avoid or Use Alternate Drug.

• methamphetamine

  Monitor Closely (1)olanzapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• methocarbamol

  Monitor Closely (1)methocarbamol and olanzapine both increase sedation. Use Caution/Monitor.

• methscopolamine

  Monitor Closely (3)methscopolamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  methscopolamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• methyldopa

  Serious - Use Alternative (1)olanzapine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

• methylene blue

  Contraindicated (1)methylene blue and fluoxetine both increase serotonin levels. Contraindicated. Methylene blue may increase serotonin as a result of MAO-A inhibition. If methylene blue must be administered, discontinue fluoxetine immediately and monitor for CNS toxicity. Fluoxetine may be resumed 24 hours after last methylene blue dose or after 5 weeks of monitoring, whichever comes first.

• methylenedioxymethamphetamine

  Monitor Closely (1)olanzapine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine increases toxicity of methylenedioxymethamphetamine by decreasing elimination. Contraindicated.

• methylergonovine

  Monitor Closely (1)methylergonovine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• methylphenidate

  Monitor Closely (1)olanzapine increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.

• methylphenidate transdermal

  Monitor Closely (1)methylphenidate transdermal will increase the level or effect of fluoxetine by decreasing metabolism. Modify Therapy/Monitor Closely. Consider decreasing the dose of these drugs when given coadministered with methylphenidate. Monitor for drug toxiticities when initiating or discontinuing methylphenidate.

• metoclopramide

  Monitor Closely (1)olanzapine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (1)metoclopramide and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. Additive effects; increased risk for serotonin syndrome, neuroleptic malignant syndrome, dystonia, or other extrapyramidal reactions

• metoclopramide intranasal

  Serious - Use Alternative (4)olanzapine increases toxicity of metoclopramide intranasal by pharmacodynamic synergism. Avoid or Use Alternate Drug. Potential for additive effects, including increased frequency and severity of tardive dyskinesia, other extrapyramidal symptoms, and neuroleptic malignant syndrome.
  
  fluoxetine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
  
  olanzapine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
  
  fluoxetine will increase the level or effect of metoclopramide intranasal by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Concurrent use of metoclopramide intranasal and strong CYP2D6 inhibitors is not recommended since the metoclopramide intranasal dose cannot be adjusted.

• metoprolol

  Serious - Use Alternative (1)fluoxetine will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• mexiletine

  Monitor Closely (1)mexiletine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• midazolam

  Monitor Closely (1)midazolam and olanzapine both increase sedation. Use Caution/Monitor.

• midazolam intranasal

  Monitor Closely (4)midazolam intranasal, fluoxetine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
  
  olanzapine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.
  
  fluoxetine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.
  
  midazolam intranasal, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• midodrine

  Monitor Closely (1)olanzapine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• midostaurin

  Serious - Use Alternative (1)olanzapine and midostaurin both increase QTc interval. Avoid or Use Alternate Drug.

• mifepristone

  Monitor Closely (2)mifepristone, fluoxetine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.
  
  mifepristone, olanzapine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.

• miglitol

  Monitor Closely (1)olanzapine, miglitol. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• milnacipran

  Monitor Closely (1)milnacipran, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fluoxetine and milnacipran both increase serotonin levels. Avoid or Use Alternate Drug.

• mipomersen

  Monitor Closely (1)mipomersen, fluoxetine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mirabegron

  Monitor Closely (1)mirabegron will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• mirtazapine

  Monitor Closely (4)olanzapine and mirtazapine both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  mirtazapine and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  olanzapine and mirtazapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)mirtazapine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• mobocertinib

  Serious - Use Alternative (2)mobocertinib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.
  
  mobocertinib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.

• modafinil

  Monitor Closely (2)modafinil will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  olanzapine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• morphine

  Monitor Closely (2)morphine and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)morphine, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• motherwort

  Monitor Closely (1)olanzapine and motherwort both increase sedation. Use Caution/Monitor.

• moxifloxacin

  Monitor Closely (1)fluoxetine and moxifloxacin both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)olanzapine and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.

• moxonidine

  Monitor Closely (1)olanzapine and moxonidine both increase sedation. Use Caution/Monitor.

• nabilone

  Monitor Closely (1)olanzapine and nabilone both increase sedation. Use Caution/Monitor.

• nabumetone

  Monitor Closely (1)fluoxetine, nabumetone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• nalbuphine

  Monitor Closely (1)nalbuphine and olanzapine both increase sedation. Use Caution/Monitor.

• naproxen

  Monitor Closely (1)fluoxetine, naproxen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• naratriptan

  Monitor Closely (2)naratriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  naratriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Minor (1)fluoxetine, naratriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• nateglinide

  Monitor Closely (2)olanzapine, nateglinide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.
  
  fluoxetine will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• nebivolol

  Serious - Use Alternative (1)fluoxetine will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• nefazodone

  Serious - Use Alternative (1)fluoxetine and nefazodone both increase serotonin levels. Avoid or Use Alternate Drug.

• netupitant/palonosetron

  Serious - Use Alternative (1)netupitant/palonosetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• nifedipine

  Monitor Closely (1)fluoxetine will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider initiating nifedipine at the lowest dose available if given concomitantly with this medication

• nilotinib

  Monitor Closely (1)fluoxetine and nilotinib both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)nilotinib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• nitisinone

  Monitor Closely (1)nitisinone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Nitisinone inhibits CYP2C9. Caution if CYP2C9 substrate coadministered, particularly those with a narrow therapeutic index.

• norepinephrine

  Monitor Closely (1)olanzapine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nortriptyline

  Monitor Closely (3)olanzapine and nortriptyline both increase sedation. Use Caution/Monitor.
  
  olanzapine and nortriptyline both increase QTc interval. Use Caution/Monitor.
  
  nortriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)fluoxetine and nortriptyline both increase serotonin levels. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• octreotide

  Monitor Closely (1)fluoxetine and octreotide both increase QTc interval. Modify Therapy/Monitor Closely.

• octreotide (Antidote)

  Monitor Closely (1)fluoxetine and octreotide (Antidote) both increase QTc interval. Modify Therapy/Monitor Closely.

• ofloxacin

  Monitor Closely (2)fluoxetine and ofloxacin both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and ofloxacin both increase QTc interval. Use Caution/Monitor.

• olanzapine

  Monitor Closely (1)olanzapine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• oliceridine

  Monitor Closely (3)fluoxetine, oliceridine. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely.
  
  fluoxetine will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
  
  oliceridine, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• olodaterol inhaled

  Monitor Closely (1)fluoxetine and olodaterol inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• olopatadine intranasal

  Serious - Use Alternative (2)fluoxetine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
  
  olanzapine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• omeprazole

  Minor (2)omeprazole will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
  
  fluoxetine will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• onabotulinumtoxinA

  Monitor Closely (3)onabotulinumtoxinA decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  onabotulinumtoxinA decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• ondansetron

  Serious - Use Alternative (3)fluoxetine and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.
  
  ondansetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.
  
  olanzapine and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.

• opium tincture

  Monitor Closely (1)opium tincture and olanzapine both increase sedation. Use Caution/Monitor.

• orphenadrine

  Monitor Closely (1)orphenadrine and olanzapine both increase sedation. Use Caution/Monitor.

• osilodrostat

  Monitor Closely (2)osilodrostat and olanzapine both increase QTc interval. Use Caution/Monitor.
  
  osilodrostat and fluoxetine both increase QTc interval. Use Caution/Monitor.

• osimertinib

  Monitor Closely (2)osimertinib and olanzapine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.
  
  osimertinib and fluoxetine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.

• oxaliplatin

  Monitor Closely (1)oxaliplatin will increase the level or effect of olanzapine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.Serious - Use Alternative (3)oxaliplatin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
  
  olanzapine and oxaliplatin both increase QTc interval. Avoid or Use Alternate Drug.
  
  oxaliplatin and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• oxaprozin

  Monitor Closely (1)fluoxetine, oxaprozin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• oxazepam

  Monitor Closely (1)oxazepam and olanzapine both increase sedation. Use Caution/Monitor.

• oxybutynin

  Monitor Closely (3)oxybutynin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxybutynin topical

  Monitor Closely (3)oxybutynin topical decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin topical decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxybutynin transdermal

  Monitor Closely (3)oxybutynin transdermal decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin transdermal decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxycodone

  Monitor Closely (1)oxycodone and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)oxycodone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Opioids may enhance the serotonergic effects of SSRIs and increase risk for serotonergic syndrome

• oxymorphone

  Monitor Closely (1)oxymorphone and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• ozanimod

  Monitor Closely (2)ozanimod and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.
  
  ozanimod and olanzapine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.Serious - Use Alternative (1)ozanimod increases toxicity of fluoxetine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.

• paliperidone

  Monitor Closely (3)olanzapine and paliperidone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and paliperidone both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and paliperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and paliperidone both increase QTc interval. Avoid or Use Alternate Drug.

• palonosetron

  Serious - Use Alternative (1)palonosetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.

• panax ginseng

  Minor (1)panax ginseng increases effects of fluoxetine by pharmacodynamic synergism. Minor/Significance Unknown.

• pancuronium

  Monitor Closely (3)pancuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  pancuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• panobinostat

  Serious - Use Alternative (2)fluoxetine and panobinostat both increase QTc interval. Avoid or Use Alternate Drug. Panobinostat is known to significantly prolong QT interval. Panobinostat prescribing information states use with drugs known to prolong QTc is not recommended.
  
  olanzapine and panobinostat both increase QTc interval. Avoid or Use Alternate Drug.

• papaveretum

  Monitor Closely (1)papaveretum and olanzapine both increase sedation. Use Caution/Monitor.

• papaverine

  Monitor Closely (1)olanzapine and papaverine both increase sedation. Use Caution/Monitor.

• parecoxib

  Monitor Closely (2)fluoxetine will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, parecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.Minor (1)parecoxib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• paroxetine

  Monitor Closely (2)paroxetine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  fluoxetine and paroxetine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (3)fluoxetine will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  olanzapine and paroxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine and paroxetine both increase serotonin levels. Avoid or Use Alternate Drug.

• pasireotide

  Monitor Closely (2)olanzapine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluoxetine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.

• pazopanib

  Minor (1)fluoxetine and pazopanib both increase QTc interval. Minor/Significance Unknown.Serious - Use Alternative (1)olanzapine and pazopanib both increase QTc interval. Avoid or Use Alternate Drug.

• pefloxacin

  Serious - Use Alternative (1)pefloxacin will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

• peginterferon alfa 2a

  Monitor Closely (1)peginterferon alfa 2a will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• peginterferon alfa 2b

  Monitor Closely (1)peginterferon alfa 2b, fluoxetine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.

• pentamidine

  Serious - Use Alternative (2)fluoxetine and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.

• pentazocine

  Monitor Closely (2)pentazocine and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.

• pentobarbital

  Monitor Closely (2)pentobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  pentobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• pentoxifylline

  Monitor Closely (1)pentoxifylline increases toxicity of fluoxetine by anticoagulation. Use Caution/Monitor. May increase bleeding.

• perhexiline

  Monitor Closely (1)fluoxetine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• perphenazine

  Monitor Closely (3)olanzapine and perphenazine both increase sedation. Use Caution/Monitor.
  
  olanzapine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and perphenazine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (3)perphenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  perphenazine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• phendimetrazine

  Monitor Closely (1)olanzapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenelzine

  Contraindicated (1)phenelzine and fluoxetine both increase serotonin levels. Contraindicated.Monitor Closely (1)phenelzine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• phenobarbital

  Monitor Closely (2)phenobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  phenobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• phentermine

  Monitor Closely (1)olanzapine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine, phentermine. Either increases toxicity of the other by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of serotonin syndrome.

• phenylephrine

  Monitor Closely (1)olanzapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine PO

  Monitor Closely (1)olanzapine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• phenytoin

  Monitor Closely (1)fluoxetine will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pholcodine

  Monitor Closely (1)olanzapine and pholcodine both increase sedation. Use Caution/Monitor.

• pimavanserin

  Serious - Use Alternative (1)olanzapine and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.

• pimozide

  Contraindicated (2)fluoxetine and pimozide both increase QTc interval. Contraindicated.
  
  fluoxetine increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.Monitor Closely (2)olanzapine and pimozide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and pimozide both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and pimozide both increase QTc interval. Contraindicated.

• pioglitazone

  Monitor Closely (1)olanzapine, pioglitazone. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• pipemidic acid

  Monitor Closely (1)pipemidic acid will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• pirbuterol

  Monitor Closely (2)olanzapine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluoxetine and pirbuterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system

• pirfenidone

  Serious - Use Alternative (1)fluoxetine will increase the level or effect of pirfenidone by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid; coadministration of pirfenidone and moderate CYP1A2 inhibitors result in moderately increased exposure to pirfenidone; if unable to avoid, decrease dose of moderate CYP1A2 inhibitor

• piroxicam

  Monitor Closely (2)fluoxetine will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine, piroxicam. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• pitolisant

  Monitor Closely (1)fluoxetine will increase the level or effect of pitolisant by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If coadministered with strong CYP2D6 inhibitors, initiate pitolisant at 8.9 mg/day and increase after 7 days to maximum of 17.8 mg/day. For patients currently taking pitolisant, reduce pitolisant dose by half upon initiating strong CYP2D6 inhibitors.Serious - Use Alternative (2)fluoxetine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.

• pleurisy root

  Minor (1)pleurisy root decreases effects of fluoxetine by unspecified interaction mechanism. Minor/Significance Unknown. Theoretical interaction.

• ponesimod

  Serious - Use Alternative (1)olanzapine and ponesimod both increase QTc interval. Avoid or Use Alternate Drug.

• posaconazole

  Monitor Closely (2)olanzapine and posaconazole both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and posaconazole both increase QTc interval. Use Caution/Monitor.

• pralidoxime

  Monitor Closely (3)pralidoxime decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  pralidoxime decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• pramipexole

  Serious - Use Alternative (1)olanzapine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

• pramlintide

  Monitor Closely (1)olanzapine, pramlintide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• pregabalin

  Monitor Closely (1)pregabalin, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• primaquine

  Monitor Closely (2)primaquine and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and primaquine both increase QTc interval. Use Caution/Monitor.

• primidone

  Monitor Closely (2)primidone will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  primidone and olanzapine both increase sedation. Use Caution/Monitor.

• procainamide

  Serious - Use Alternative (2)fluoxetine and procainamide both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and procainamide both increase QTc interval. Avoid or Use Alternate Drug.

• procarbazine

  Contraindicated (1)procarbazine and fluoxetine both increase serotonin levels. Contraindicated. Combinations is contraindicated within 5 weeks of MAOI use.Monitor Closely (1)procarbazine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• prochlorperazine

  Monitor Closely (5)olanzapine and prochlorperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  olanzapine and prochlorperazine both decrease QTc interval. Use Caution/Monitor.
  
  olanzapine and prochlorperazine both increase sedation. Use Caution/Monitor.
  
  prochlorperazine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• promazine

  Monitor Closely (2)promazine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluoxetine will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• promethazine

  Monitor Closely (5)promethazine and olanzapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and promethazine both decrease QTc interval. Use Caution/Monitor.
  
  promethazine and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  promethazine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fluoxetine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• propafenone

  Serious - Use Alternative (4)propafenone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  olanzapine and propafenone both increase QTc interval. Avoid or Use Alternate Drug.
  
  propafenone and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• propantheline

  Monitor Closely (3)propantheline decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  propantheline decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• propofol

  Monitor Closely (1)propofol and olanzapine both increase sedation. Use Caution/Monitor.

• propranolol

  Serious - Use Alternative (1)fluoxetine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• propylhexedrine

  Monitor Closely (1)olanzapine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• protriptyline

  Monitor Closely (3)olanzapine and protriptyline both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and protriptyline both increase sedation. Use Caution/Monitor.
  
  protriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)fluoxetine and protriptyline both increase serotonin levels. Avoid or Use Alternate Drug.

• quazepam

  Monitor Closely (1)quazepam and olanzapine both increase sedation. Use Caution/Monitor.

• quetiapine

  Monitor Closely (3)quetiapine, fluoxetine. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.
  
  olanzapine and quetiapine both increase sedation. Use Caution/Monitor.
  
  olanzapine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• quinacrine

  Minor (1)quinacrine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• quinidine

  Serious - Use Alternative (3)olanzapine and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
  
  quinidine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  quinidine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• quinine

  Monitor Closely (2)fluoxetine and quinine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and quinine both increase QTc interval. Use Caution/Monitor.

• rabeprazole

  Minor (1)fluoxetine will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• ramelteon

  Monitor Closely (2)fluoxetine will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  olanzapine and ramelteon both increase sedation. Use Caution/Monitor.

• ranolazine

  Monitor Closely (1)fluoxetine and ranolazine both increase QTc interval. Use Caution/Monitor.Minor (1)ranolazine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.Serious - Use Alternative (1)olanzapine and ranolazine both increase QTc interval. Avoid or Use Alternate Drug.

• rapacuronium

  Monitor Closely (3)rapacuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  rapacuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• rasagiline

  Serious - Use Alternative (1)rasagiline and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. evere CNS toxicity associated with hyperpyrexia has been reported with the combined treatment of an antidepressant and rasagiline. Avoid combination within 14 days of MAOI use.

• remifentanil

  Monitor Closely (1)remifentanil, fluoxetine. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely.

• remimazolam

  Monitor Closely (2)remimazolam, fluoxetine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.
  
  remimazolam, olanzapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.

• repaglinide

  Monitor Closely (1)olanzapine, repaglinide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• ribociclib

  Serious - Use Alternative (3)ribociclib increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug.
  
  ribociclib will increase the level or effect of fluoxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  ribociclib increases toxicity of olanzapine by QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.

• rifampin

  Monitor Closely (1)rifampin will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• rilpivirine

  Monitor Closely (2)olanzapine and rilpivirine both increase QTc interval. Use Caution/Monitor.
  
  rilpivirine increases toxicity of fluoxetine by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsades de Pointes.

• rimabotulinumtoxinB

  Monitor Closely (1)olanzapine, rimabotulinumtoxinB. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• risperidone

  Monitor Closely (4)olanzapine and risperidone both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and risperidone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and risperidone both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• ritonavir

  Monitor Closely (1)ritonavir decreases levels of olanzapine by increasing metabolism. Use Caution/Monitor.Minor (1)ritonavir will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• rivaroxaban

  Monitor Closely (1)fluoxetine increases effects of rivaroxaban by pharmacodynamic synergism. Use Caution/Monitor. Combination may increase risk of bleeding.

• rizatriptan

  Monitor Closely (1)rizatriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)fluoxetine, rizatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• rocuronium

  Monitor Closely (3)rocuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  rocuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• rolapitant

  Monitor Closely (1)rolapitant will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.

• romidepsin

  Monitor Closely (2)olanzapine and romidepsin both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine and romidepsin both increase QTc interval. Use Caution/Monitor.

• ropinirole

  Serious - Use Alternative (1)olanzapine decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

• rosiglitazone

  Monitor Closely (1)olanzapine, rosiglitazone. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• rucaparib

  Monitor Closely (2)rucaparib will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP1A2 substrates, if clinically indicated.
  
  rucaparib will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C9 substrates, if clinically indicated.

• ruxolitinib

  Minor (2)fluoxetine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  olanzapine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ruxolitinib topical

  Minor (2)olanzapine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  fluoxetine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• safinamide

  Monitor Closely (1)fluoxetine, safinamide. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Monitor patients for symptoms of serotonin syndrome if SSRIs are coadministered with safinamide.Serious - Use Alternative (1)olanzapine decreases effects of safinamide by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Dopamine antagonists may decrease safinamide effects and exacerbate Parkinson disease symptoms.

• sage

  Minor (1)olanzapine and sage both increase sedation. Minor/Significance Unknown.

• salicylates (non-asa)

  Monitor Closely (1)fluoxetine, salicylates (non-asa). Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• salmeterol

  Monitor Closely (2)fluoxetine and salmeterol both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system
  
  olanzapine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salsalate

  Monitor Closely (1)fluoxetine, salsalate. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• SAMe

  Monitor Closely (1)fluoxetine and SAMe both increase serotonin levels. Modify Therapy/Monitor Closely.

• saquinavir

  Monitor Closely (1)saquinavir and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)olanzapine and saquinavir both increase QTc interval. Avoid or Use Alternate Drug.

• saxagliptin

  Monitor Closely (1)olanzapine, saxagliptin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• scopolamine

  Monitor Closely (3)scopolamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  scopolamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of scopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• scullcap

  Monitor Closely (1)olanzapine and scullcap both increase sedation. Use Caution/Monitor.

• secobarbital

  Monitor Closely (2)secobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  secobarbital and olanzapine both increase sedation. Use Caution/Monitor.

• selegiline

  Contraindicated (1)selegiline and fluoxetine both increase serotonin levels. Contraindicated. At least 5 weeks should elapse between discontinuation of fluoxetine and initiation of selegiline.Monitor Closely (1)selegiline, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• selegiline transdermal

  Serious - Use Alternative (1)selegiline transdermal and fluoxetine both decrease serotonin levels. Avoid or Use Alternate Drug.

• selinexor

  Serious - Use Alternative (2)selinexor, fluoxetine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.
  
  selinexor, olanzapine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

• selpercatinib

  Monitor Closely (2)selpercatinib increases toxicity of olanzapine by QTc interval. Use Caution/Monitor.
  
  selpercatinib increases toxicity of fluoxetine by QTc interval. Use Caution/Monitor.

• serdexmethylphenidate/dexmethylphenidate

  Minor (1)serdexmethylphenidate/dexmethylphenidate increases effects of fluoxetine by decreasing metabolism. Minor/Significance Unknown.

• sertraline

  Monitor Closely (2)olanzapine and sertraline both increase QTc interval. Use Caution/Monitor.
  
  sertraline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)sertraline will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
  
  fluoxetine and sertraline both increase serotonin levels. Avoid or Use Alternate Drug.

• sevoflurane

  Serious - Use Alternative (2)sevoflurane and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  sevoflurane and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• shepherd's purse

  Monitor Closely (1)olanzapine and shepherd's purse both increase sedation. Use Caution/Monitor.

• siponimod

  Serious - Use Alternative (3)siponimod and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and siponimod both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.

• sitagliptin

  Monitor Closely (1)olanzapine, sitagliptin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• smoking

  Monitor Closely (1)smoking will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• sodium oxybate

  Serious - Use Alternative (1)olanzapine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Monitor Closely (2)sodium sulfate/?magnesium sulfate/potassium chloride increases effects of olanzapine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases effects of fluoxetine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of seizures when using bowel preps together with drugs that lower the seizure threshold.

• sodium sulfate/potassium sulfate/magnesium sulfate

  Monitor Closely (2)sodium sulfate/potassium sulfate/magnesium sulfate increases effects of fluoxetine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of seizures when using bowel preps together with drugs that lower the seizure threshold.
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases effects of olanzapine by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.

• sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol

  Monitor Closely (1)fluoxetine, sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol. Other (see comment). Use Caution/Monitor. Comment: Caution when bowel preps are used with drugs that cause SIADH or NSAIDs; increased risk for water retention or electrolyte imbalance.

• solifenacin

  Monitor Closely (5)solifenacin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  olanzapine increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  solifenacin and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  solifenacin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine and solifenacin both increase QTc interval. Use Caution/Monitor.

• sorafenib

  Monitor Closely (2)sorafenib and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  sorafenib and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• sotalol

  Serious - Use Alternative (2)fluoxetine and sotalol both increase QTc interval. Avoid or Use Alternate Drug.
  
  olanzapine and sotalol both increase QTc interval. Avoid or Use Alternate Drug.

• sparsentan

  Monitor Closely (1)sparsentan will decrease the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C9 inducer) decreases exposure of CYP2C9 substrates and reduces efficacy related to these substrates.

• St John's Wort

  Serious - Use Alternative (1)fluoxetine and St John's Wort both increase serotonin levels. Avoid or Use Alternate Drug.

• stiripentol

  Monitor Closely (2)stiripentol, olanzapine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.
  
  stiripentol, olanzapine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP1A2 inhibitor and inducer. Monitor CYP1A2 substrates coadministered with stiripentol for increased or decreased effects. CYP1A2 substrates may require dosage adjustment.

• sufentanil

  Monitor Closely (1)sufentanil and olanzapine both increase sedation. Use Caution/Monitor.

• sufentanil SL

  Monitor Closely (1)sufentanil SL, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.Serious - Use Alternative (1)sufentanil SL, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• sulfamethoxazole

  Monitor Closely (1)fluoxetine will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• sulfasalazine

  Monitor Closely (1)fluoxetine, sulfasalazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• sulindac

  Monitor Closely (1)fluoxetine, sulindac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• sumatriptan

  Monitor Closely (2)sumatriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  sumatriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)fluoxetine, sumatriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• sumatriptan intranasal

  Monitor Closely (2)sumatriptan intranasal, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  sumatriptan intranasal and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)fluoxetine, sumatriptan intranasal. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• sunitinib

  Monitor Closely (2)olanzapine and sunitinib both increase QTc interval. Use Caution/Monitor.
  
  sunitinib and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• tacrolimus

  Monitor Closely (2)tacrolimus and fluoxetine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and tacrolimus both increase QTc interval. Use Caution/Monitor.

• tamoxifen

  Monitor Closely (1)fluoxetine will decrease the level or effect of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.

• tamsulosin

  Monitor Closely (1)fluoxetine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• tapentadol

  Monitor Closely (2)fluoxetine and tapentadol both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  tapentadol and olanzapine both increase sedation. Use Caution/Monitor.

• tazemetostat

  Monitor Closely (2)olanzapine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tedizolid

  Serious - Use Alternative (1)tedizolid, fluoxetine. Either increases effects of the other by Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. both increase serotonin levels; increased risk of serotonin syndrome.

• telavancin

  Monitor Closely (2)fluoxetine and telavancin both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and telavancin both increase QTc interval. Use Caution/Monitor.

• temazepam

  Monitor Closely (1)temazepam and olanzapine both increase sedation. Use Caution/Monitor.

• terbinafine

  Monitor Closely (1)terbinafine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.

• terbutaline

  Monitor Closely (2)fluoxetine and terbutaline both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular system
  
  olanzapine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• teriflunomide

  Monitor Closely (1)teriflunomide decreases levels of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• tetrabenazine

  Monitor Closely (2)fluoxetine increases effects of tetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Decrease tetrabenazine dose by 50% when coadministered with strong CYP2D6 inhibitors.
  
  olanzapine and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)olanzapine and tetrabenazine both increase QTc interval. Avoid or Use Alternate Drug.
  
  tetrabenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.

• thioridazine

  Contraindicated (4)olanzapine and thioridazine both increase QTc interval. Contraindicated.
  
  fluoxetine increases levels of thioridazine by decreasing metabolism. Contraindicated. Risk of long QT syndrome.
  
  thioridazine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.
  
  thioridazine and fluoxetine both increase QTc interval. Contraindicated.Monitor Closely (2)olanzapine and thioridazine both increase sedation. Use Caution/Monitor.
  
  olanzapine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• thiothixene

  Monitor Closely (3)olanzapine and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  thiothixene and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and thiothixene both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and thiothixene both increase QTc interval. Avoid or Use Alternate Drug.

• timolol

  Serious - Use Alternative (1)fluoxetine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• tinidazole

  Monitor Closely (2)fluoxetine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  olanzapine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tiotropium

  Monitor Closely (3)tiotropium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tiotropium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• tipranavir

  Serious - Use Alternative (1)tipranavir will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• tobacco use

  Monitor Closely (1)tobacco use will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• tolazamide

  Monitor Closely (2)fluoxetine increases effects of tolazamide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  olanzapine, tolazamide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• tolbutamide

  Monitor Closely (3)fluoxetine increases effects of tolbutamide by unspecified interaction mechanism. Use Caution/Monitor. Risk of hypoglycemia.
  
  fluoxetine will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  olanzapine, tolbutamide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.

• tolfenamic acid

  Monitor Closely (1)fluoxetine, tolfenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• tolmetin

  Monitor Closely (1)fluoxetine, tolmetin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• tolterodine

  Monitor Closely (3)olanzapine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  tolterodine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tolterodine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• topiramate

  Monitor Closely (1)olanzapine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• toremifene

  Monitor Closely (1)toremifene and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)olanzapine and toremifene both increase QTc interval. Avoid or Use Alternate Drug.

• torsemide

  Minor (1)torsemide, fluoxetine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Possible additive hyponatremia.

• tramadol

  Monitor Closely (2)tramadol and olanzapine both increase sedation. Use Caution/Monitor.
  
  fluoxetine and tramadol both increase serotonin levels. Modify Therapy/Monitor Closely.

• tranylcypromine

  Contraindicated (1)tranylcypromine and fluoxetine both increase serotonin levels. Contraindicated.Monitor Closely (1)tranylcypromine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• trazodone

  Monitor Closely (2)trazodone and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and trazodone both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)fluoxetine and trazodone both increase serotonin levels. Avoid or Use Alternate Drug.
  
  olanzapine and trazodone both increase QTc interval. Avoid or Use Alternate Drug.

• triazolam

  Monitor Closely (1)triazolam and olanzapine both increase sedation. Use Caution/Monitor.

• triclabendazole

  Monitor Closely (2)triclabendazole and olanzapine both increase QTc interval. Use Caution/Monitor.
  
  triclabendazole and fluoxetine both increase QTc interval. Use Caution/Monitor.

• triclofos

  Monitor Closely (1)triclofos and olanzapine both increase sedation. Use Caution/Monitor.

• trifluoperazine

  Monitor Closely (5)olanzapine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  trifluoperazine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluoxetine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  olanzapine and trifluoperazine both increase sedation. Use Caution/Monitor.
  
  olanzapine and trifluoperazine both decrease QTc interval. Use Caution/Monitor.

• trihexyphenidyl

  Monitor Closely (1)olanzapine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

• trimethoprim

  Monitor Closely (1)fluoxetine and trimethoprim both increase QTc interval. Use Caution/Monitor.

• trimipramine

  Monitor Closely (3)olanzapine and trimipramine both increase QTc interval. Use Caution/Monitor.
  
  trimipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and trimipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine and trimipramine both increase serotonin levels. Avoid or Use Alternate Drug.

• triprolidine

  Monitor Closely (1)triprolidine and olanzapine both increase sedation. Use Caution/Monitor.

• triptorelin

  Serious - Use Alternative (2)olanzapine and triptorelin both increase QTc interval. Avoid or Use Alternate Drug.
  
  triptorelin increases toxicity of fluoxetine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• tropisetron

  Monitor Closely (2)fluoxetine will increase the level or effect of tropisetron by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  fluoxetine and tropisetron both increase QTc interval. Use Caution/Monitor.

• trospium chloride

  Monitor Closely (3)trospium chloride decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  trospium chloride decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• umeclidinium bromide/vilanterol inhaled

  Monitor Closely (1)fluoxetine and umeclidinium bromide/vilanterol inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular systemSerious - Use Alternative (1)olanzapine increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

• valbenazine

  Monitor Closely (3)valbenazine and olanzapine both increase QTc interval. Use Caution/Monitor.
  
  fluoxetine will increase the level or effect of valbenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Consider reducing valbenazine dose based on tolerability if coadministered with a strong CYP2D6 inhibitor.
  
  valbenazine and fluoxetine both increase QTc interval. Use Caution/Monitor.

• valerian

  Monitor Closely (1)valerian and fluoxetine both increase sedation. Use Caution/Monitor.

• vandetanib

  Serious - Use Alternative (2)olanzapine and vandetanib both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine, vandetanib. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. Avoid coadministration with drugs known to prolong QT interval; if a drug known to prolong QT interval must be used, more frequent ECG monitoring is recommended.

• vardenafil

  Monitor Closely (2)olanzapine and vardenafil both increase QTc interval. Use Caution/Monitor.
  
  vardenafil and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• vecuronium

  Monitor Closely (3)vecuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  vecuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  olanzapine increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• vemurafenib

  Serious - Use Alternative (2)olanzapine and vemurafenib both increase QTc interval. Avoid or Use Alternate Drug.
  
  vemurafenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended.

• venlafaxine

  Monitor Closely (3)fluoxetine and venlafaxine both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and venlafaxine both decrease QTc interval. Use Caution/Monitor.
  
  venlafaxine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fluoxetine and venlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.Minor (1)venlafaxine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• verapamil

  Monitor Closely (1)verapamil will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• vilanterol/fluticasone furoate inhaled

  Monitor Closely (1)fluoxetine and vilanterol/fluticasone furoate inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular systemSerious - Use Alternative (1)olanzapine increases toxicity of vilanterol/fluticasone furoate inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

• vilazodone

  Monitor Closely (1)vilazodone, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fluoxetine, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .

• voclosporin

  Monitor Closely (2)voclosporin, olanzapine. Either increases effects of the other by QTc interval. Use Caution/Monitor.
  
  voclosporin, fluoxetine. Either increases effects of the other by QTc interval. Use Caution/Monitor.

• vorapaxar

  Monitor Closely (1)fluoxetine, vorapaxar. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive antiplatelet effect may occur; SSRIs and SNRIs may cause platelet serotonin depletion .

• voriconazole

  Monitor Closely (3)fluoxetine will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  fluoxetine and voriconazole both increase QTc interval. Use Caution/Monitor.
  
  olanzapine and voriconazole both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)fluoxetine will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• vorinostat

  Monitor Closely (2)olanzapine and vorinostat both increase QTc interval. Use Caution/Monitor.
  
  vorinostat and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.

• vortioxetine

  Serious - Use Alternative (1)fluoxetine, vortioxetine. Either increases effects of the other by serotonin levels. Avoid or Use Alternate Drug.

• warfarin

  Monitor Closely (1)fluoxetine, warfarin. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Serotonin release by platelets plays an important role in hemostasis. SSRIs and SNRIs may increase anticoagulation effect of warfarin. .

• xylometazoline

  Monitor Closely (1)olanzapine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• yohimbine

  Monitor Closely (1)olanzapine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• zanubrutinib

  Monitor Closely (1)fluoxetine, zanubrutinib. Either increases effects of the other by anticoagulation. Modify Therapy/Monitor Closely. Zanubrutinib-induced cytopenias increases risk of hemorrhage. Coadministration of zanubritinib with antiplatelets or anticoagulants may further increase this risk.

• ziconotide

  Monitor Closely (1)olanzapine and ziconotide both increase sedation. Use Caution/Monitor.

• zileuton

  Monitor Closely (1)zileuton will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• ziprasidone

  Monitor Closely (3)olanzapine and ziprasidone both increase sedation. Use Caution/Monitor.
  
  fluoxetine and ziprasidone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  olanzapine and ziprasidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.

• zolmitriptan

  Monitor Closely (2)zolmitriptan, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).
  
  zolmitriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)fluoxetine, zolmitriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.

• zotepine

  Monitor Closely (3)olanzapine and zotepine both increase sedation. Use Caution/Monitor.
  
  olanzapine and zotepine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluoxetine increases levels of zotepine by decreasing metabolism. Use Caution/Monitor.