quetiapine (Rx)

Schizophrenia

Immediate release

• Day 1: 50 mg/day PO divided q12hr
• Days 2-3: Dose increased daily in increments of 25-50 mg q8-12hr to 300-400 mg by day 4; further adjustments can be made in increments of 25-50 mg q12hr at intervals ≥2 days
• Dosage range: 150-750 mg/day

Extended release

• Day 1: 300 mg/day PO; subsequently, may be increased by up to 300 mg/day at intervals ≥1 day
• Maintenance (monotherapy): 400-800 mg/day
• Patients who have discontinued therapy for >1 week should have their dose retitrated following initiation of therapy; patients may reinitiate at their previous maintenance dose if discontinued therapy <1 week

Bipolar I Disorder, Mania

Administered as monotherapy or as adjunct to lithium or divalproex

Immediate release

• Day 1: 100 mg/day PO divided q12hr
• Day 2: 200 mg/day PO divided q12hr
• Day 3: 300 mg/day PO divided q12hr
• Day 4: 400 mg/day PO divided q12hr
• Further dosage adjustments, up to 800 mg/day by day 6, should be in increments ≤200 mg/day
• Dosage range: 400-800 mg/day; not to exceed 800 mg/day

Extended release

• Day 1: 300 mg PO once daily
• Day 2: 600 mg PO once daily
• Maintenance (day 3 onward): 400-800 mg/day PO

Bipolar Disorder, Depressive Episodes

Either immediate-release or extended-release tablets may be given; dosage titrated upward over 4 days

Day 1: 50 mg PO at bedtime

Day 2: 100 mg PO at bedtime

Day 3: 200 mg PO at bedtime

Maintenance (day 4 onward): 300 mg PO at bedtime

Bipolar I Disorder, Maintenance

Administered as adjunct to lithium or divalproex

Immediate release: 400-800 mg/day PO divided q12hr

Extended release: 400-800 mg/day PO in single dose

Generally, in maintenance phase, patients continue to receive same dosage on which they were stabilized

Major Depressive Disorder

Extended-release formulation administered as adjunct to antidepressants

Days 1 and 2: 50 mg PO in evening

Day 3: May be increased to 150 mg PO in evening

Dosage range: 150-300 mg/day

Alcohol Dependence (Off-label)

25-50 mg PO at bedtime; may be titrated; not to exceed 300 mg

Insomnia (Off-label)

Usually, 25 mg/day PO at bedtime initially

Administration

Preferably, take in evening without food or with light meal

Switching from immediate release to extended release

• Convert to extended release tablets at equivalent immediate release total daily dose; administer once daily; individual adjustments may be necessary

Schizophrenia

<12 years

• Safety and efficacy not established

>12 years (monotherapy, immediate release)

• Day 1: 50 mg/day PO divided q12hr
• Day 2: 100 mg/day PO divided q12hr
• Day 3: 200 mg/day PO divided q12hr
• Day 4: 300 mg/day PO divided q12hr
• Day 5: 400 mg/day PO divided q12hr; further adjustments should be in increments ≤100 mg/day
• Dosage range: 400-800 mg/day
• Depending on response and tolerance, daily dose may be divided q8hr

>12 years (monotherapy, extended release)

• Day 1: 50 mg/day PO once daily
• Day 2: 100 mg/day PO once daily
• Day 3: 200 mg/day PO once daily
• Day 4: 300 mg/day PO once daily
• Day 5: 400 mg/day PO once daily; further adjustments should be in increments ≤100 mg/day

Bipolar I Disorder, Mania

<10 years

• Safety and efficacy not established

>10 years (monotherapy, immediate release)

• Day 1: 50 mg/day PO divided q12hr
• Day 2: 100 mg/day PO divided q12hr
• Day 3: 200 mg/day PO divided q12hr
• Day 4: 300 mg/day PO divided q12hr
• Day 5: 400 mg/day PO divided q12hr; further adjustments should be in increments ≤100 mg/day
• Dosage range: 400-600 mg/day
• Depending on response and tolerance, daily dose may be divided q8hr

>10 years (monotherapy, extended release)

• Day 1: 50 mg/day PO once daily
• Day 2: 100 mg/day PO once daily
• Day 3: 200 mg/day PO once daily
• Day 4: 300 mg/day PO once daily
• Day 5: 400 mg/day PO once daily; further adjustments should be in increments ≤100 mg/day
• Dosage range: 400-600 mg once daily

Not approved for dementia-related psychosis, because of increased risk of cardiovascular or infectious related deaths (see Black Box Warnings)

Schizophrenia, Bipolar Disorder

Immediate release: 50-200 mg/day PO; may be increased by 25-50 mg/day

Extended release: 50 mg/day PO; may be increased by 50 mg/day

Psychosis, Agitation Related to Alzheimer Dementia (Off-label)

12.5-50 mg/day PO initially; may be gradually increased as tolerated; not to exceed 200-300 mg/day

Contraindicated (4)

• amisulpride

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

• goserelin

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

• lefamulin

  lefamulin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.

• leuprolide

  leuprolide increases toxicity of quetiapine by QTc interval. Contraindicated. Increases risk of torsades de pointes.

Serious - Use Alternative (87)

• abametapir

  abametapir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

• alfuzosin

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

• amisulpride

  amisulpride and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.

• apalutamide

  apalutamide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

• apomorphine

  quetiapine decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• aripiprazole

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

• artemether

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

• atazanavir

  atazanavir increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternative anti-HCV therapy to avoid increases in quetiapine exposures; if coadministration is necessary, reduce quetiapine dose to 1/6th of current dose and monitor for quetiapine associated adverse reactions; refer to quetiapine prescribing information for recommendations on adverse reaction monitoring.

• atomoxetine

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

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen, quetiapine. 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

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

• cabergoline

  quetiapine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

• calcium/magnesium/potassium/sodium oxybates

  quetiapine, 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.

• carbamazepine

  carbamazepine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ceritinib

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

• chloramphenicol

  chloramphenicol will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cimetidine

  cimetidine will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• clarithromycin

  clarithromycin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• clozapine

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

• cobicistat

  cobicistat increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with atazanavir and cobicistat in patients taking quetiapine. If coadministration is necessary, reduce quetiapine dose to one-sixth of the current dose and monitor for quetiapine-associated adverse reactions. Refer to quetiapine prescribing information for initial dosing and titration of quetiapine.

• crizotinib

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

• dabrafenib

  dabrafenib will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• desflurane

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

• donepezil

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

• dopamine

  quetiapine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

• efavirenz

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

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with quetiapine. If coadministration is necessary, reduce quetiapine dose to one-sixth of the current dose.

• encorafenib

  encorafenib and quetiapine 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.

• entrectinib

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

• enzalutamide

  enzalutamide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eribulin

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

• erythromycin base

  erythromycin base will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  erythromycin ethylsuccinate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  erythromycin lactobionate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  erythromycin stearate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• escitalopram

  escitalopram increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug.

• fexinidazole

  fexinidazole and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels and/or prolong QT interval.
  
  fexinidazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

• fingolimod

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

• gilteritinib

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

• glasdegib

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

• granisetron

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

• histrelin

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

• hydrocodone

  hydrocodone, quetiapine. 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.

• hydroxychloroquine sulfate

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

• hydroxyzine

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

• idelalisib

  idelalisib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• inotuzumab

  inotuzumab and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. If unable to avoid concomitant use, obtain ECGs and electrolytes before and after initiation of any drug known to prolong QTc, and periodically monitor as clinically indicated during treatment.

• isoflurane

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

• itraconazole

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

• ivosidenib

  ivosidenib and quetiapine 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• levodopa

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

• levodopa inhaled

  quetiapine 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

  quetiapine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

• lithium

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

• lonafarnib

  lonafarnib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.

• lopinavir

  lopinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• macimorelin

  macimorelin and quetiapine 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.

• mefloquine

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

• methyldopa

  quetiapine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

• metoclopramide intranasal

  quetiapine, 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.
  
  quetiapine 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.

• mifepristone

  mifepristone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• mirtazapine

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

• mobocertinib

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

• nefazodone

  nefazodone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternative anti-HCV therapy to avoid increases in quetiapine exposures; if coadministration necessary, reduce quetiapine dose to 1/6th of current dose and monitor for quetiapine associated adverse reactions; refer to quetiapine prescribing information for recommendations on adverse reaction monitoring

• ondansetron

  quetiapine 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.

• panobinostat

  quetiapine 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.

• pimavanserin

  pimavanserin and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.

• pitolisant

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

• pramipexole

  quetiapine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

• ribociclib

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

• rifabutin

  rifabutin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rifampin

  rifampin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ropinirole

  quetiapine decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

• safinamide

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

• saquinavir

  saquinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• selinexor

  selinexor, quetiapine. 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.

• sevoflurane

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

• sodium oxybate

  quetiapine, 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

  St John's Wort will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sufentanil SL

  sufentanil SL, quetiapine. 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.

• triptorelin

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

• tucatinib

  tucatinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

• umeclidinium bromide/vilanterol inhaled

  quetiapine 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.

• vemurafenib

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

• vilanterol/fluticasone furoate inhaled

  quetiapine 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.

• voxelotor

  voxelotor will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

Monitor Closely (424)

• abobotulinumtoxinA

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

• acarbose

  quetiapine, 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.

• aclidinium

  aclidinium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• albiglutide

  quetiapine, 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

  quetiapine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  albuterol and quetiapine both increase QTc interval. Use Caution/Monitor.

• alfentanil

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

• alfuzosin

  quetiapine and alfuzosin both increase QTc interval. Use Caution/Monitor.

• almotriptan

  almotriptan, quetiapine. 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).

• alprazolam

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

• amifostine

  amifostine, quetiapine. 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

  quetiapine, amiodarone. 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.

• amitriptyline

  quetiapine and amitriptyline both increase sedation. Use Caution/Monitor.
  
  quetiapine, amitriptyline. 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.

• amobarbital

  amobarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  amobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• amoxapine

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

• anticholinergic/sedative combos

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

• apomorphine

  quetiapine and apomorphine both increase sedation. Use Caution/Monitor.
  
  quetiapine, apomorphine. 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.

• aprepitant

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

• arformoterol

  quetiapine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  arformoterol and quetiapine both increase QTc interval. Use Caution/Monitor.

• aripiprazole

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

• armodafinil

  armodafinil will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• arsenic trioxide

  quetiapine, arsenic trioxide. 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.

• artemether/lumefantrine

  artemether/lumefantrine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, artemether/lumefantrine. 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.

• asenapine

  quetiapine, asenapine. 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.

• atracurium

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

• atropine

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

• atropine IV/IM

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

• azelastine

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

• azithromycin

  quetiapine, azithromycin. 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.

• baclofen

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

• bedaquiline

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

• belladonna alkaloids

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

• belladonna and opium

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

• benazepril

  quetiapine increases toxicity of benazepril by pharmacodynamic synergism. Use Caution/Monitor. Increases risk of hypotension.
  
  benazepril increases toxicity of quetiapine by pharmacodynamic synergism. Use Caution/Monitor. Increases risk of hypotension.

• benperidol

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

• benzphetamine

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

• benztropine

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

• bosentan

  bosentan will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexanolone

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

• brompheniramine

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

• budesonide

  budesonide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine

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

• buprenorphine buccal

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

• buprenorphine, long-acting injection

  quetiapine 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.

• butabarbital

  butabarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  butabarbital and quetiapine both increase sedation. Use Caution/Monitor.

• butalbital

  butalbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  butalbital and quetiapine both increase sedation. Use Caution/Monitor.

• butorphanol

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

• caffeine

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

• captopril

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

• carbamazepine

  quetiapine will increase the level or effect of carbamazepine by decreasing metabolism. Modify Therapy/Monitor Closely. Monitor plasma levels when used concomitantly

• carbinoxamine

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

• carisoprodol

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

• cenobamate

  cenobamate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
  
  cenobamate, quetiapine. Either increases effects of the other by sedation. Use Caution/Monitor.

• chloral hydrate

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

• chlordiazepoxide

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

• chloroquine

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

• chlorpheniramine

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

• chlorpromazine

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

• chlorpropamide

  quetiapine, 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 quetiapine both increase sedation. Use Caution/Monitor.

• cinnarizine

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

• ciprofloxacin

  quetiapine, ciprofloxacin. 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.

• cisatracurium

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

• citalopram

  quetiapine, citalopram. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT interval 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. ECG monitoring is recommended.

• clarithromycin

  quetiapine, clarithromycin. 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.

• clemastine

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

• clobazam

  quetiapine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

• clomipramine

  quetiapine and clomipramine both increase sedation. Use Caution/Monitor.
  
  quetiapine, clomipramine. 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.

• clonazepam

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

• clonidine

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

• clorazepate

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

• clozapine

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

• codeine

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

• conivaptan

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

• cortisone

  cortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• crizotinib

  crizotinib increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

• crofelemer

  crofelemer increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

• cyclizine

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

• cyclobenzaprine

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

• cyclosporine

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

• cyproheptadine

  cyproheptadine and quetiapine both increase sedation. Use Caution/Monitor.

• dantrolene

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

• daridorexant

  quetiapine 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 will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  darifenacin decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  darifenacin decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• darunavir

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

• dasatinib

  dasatinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, dasatinib. 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.

• deferasirox

  deferasirox will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• degarelix

  quetiapine, degarelix. 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.

• desflurane

  desflurane and quetiapine both increase sedation. Use Caution/Monitor.

• desipramine

  quetiapine and desipramine both increase sedation. Use Caution/Monitor.
  
  quetiapine, desipramine. 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.

• deutetrabenazine

  quetiapine 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.
  
  quetiapine and deutetrabenazine both increase sedation. Use Caution/Monitor.
  
  quetiapine and deutetrabenazine both increase QTc interval. Modify Therapy/Monitor Closely. For patients requiring deutetrabenazine doses >24 mg/day and are taking other drugs known to prolong QTc, assess the QTc interval before and after increasing the dose of deutetrabenazine or other medications known to prolong QTc.

• dexamethasone

  dexamethasone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dexchlorpheniramine

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

• dexfenfluramine

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

• dexmedetomidine

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

• dexmethylphenidate

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

• dextroamphetamine

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

• dextromethorphan

  dextromethorphan, quetiapine. 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 quetiapine both increase sedation. Use Caution/Monitor.

• DHEA, herbal

  DHEA, herbal will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diamorphine

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

• diazepam

  diazepam and quetiapine both increase sedation. Use Caution/Monitor.

• dichlorphenamide

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

• dicyclomine

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

• diethylpropion

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

• difelikefalin

  difelikefalin and quetiapine both increase sedation. Use Caution/Monitor.

• difenoxin hcl

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

• dihydroergotamine

  dihydroergotamine, quetiapine. 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).

• diltiazem

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

• dimenhydrinate

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

• diphenhydramine

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

• diphenoxylate hcl

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

• dipipanone

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

• disopyramide

  quetiapine, disopyramide. 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.

• dobutamine

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

• dofetilide

  quetiapine, dofetilide. 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.
  
  dofetilide increases toxicity of quetiapine by QTc interval. Use Caution/Monitor.

• dolasetron

  quetiapine, dolasetron. 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.

• donepezil transdermal

  quetiapine, donepezil transdermal. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.

• dopamine

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

• dopexamine

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

• dosulepin

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

• doxepin

  quetiapine and doxepin both increase sedation. Use Caution/Monitor.
  
  doxepin and quetiapine both increase QTc interval. Use Caution/Monitor.

• doxylamine

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

• dronedarone

  dronedarone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, dronedarone. 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.

• droperidol

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

• duvelisib

  duvelisib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.

• efavirenz

  efavirenz will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• elagolix

  elagolix decreases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

• eletriptan

  eletriptan, quetiapine. 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).

• encorafenib

  encorafenib, quetiapine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

• ephedrine

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

• epinephrine

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

• epinephrine racemic

  quetiapine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ergoloid mesylates

  ergoloid mesylates, quetiapine. 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

  ergotamine, quetiapine. 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).

• erythromycin base

  quetiapine, erythromycin base. 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.

• erythromycin ethylsuccinate

  quetiapine, erythromycin ethylsuccinate. 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.

• erythromycin lactobionate

  quetiapine, erythromycin lactobionate. 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.

• erythromycin stearate

  quetiapine, erythromycin stearate. 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.

• escitalopram

  quetiapine, escitalopram. 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.

• esketamine intranasal

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

• eslicarbazepine acetate

  eslicarbazepine acetate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estazolam

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

• ethanol

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

• etravirine

  etravirine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• exenatide injectable solution

  quetiapine, 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

  quetiapine, 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, quetiapine. Either increases toxicity of the other by 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

• fenfluramine

  quetiapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  quetiapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.

• fentanyl

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

• flavoxate

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

• flecainide

  quetiapine, flecainide. 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.

• flibanserin

  flibanserin, quetiapine. 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).

• fluconazole

  fluconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, fluconazole. 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.

• fludrocortisone

  fludrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fluoxetine

  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.

• fluphenazine

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

• flurazepam

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

• fluvoxamine

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

• formoterol

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

• fosamprenavir

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

• foscarnet

  quetiapine, foscarnet. 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.

• fosphenytoin

  fosphenytoin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fostemsavir

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

• frovatriptan

  frovatriptan, quetiapine. 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).

• gadobenate

  gadobenate and quetiapine both increase QTc interval. Use Caution/Monitor.

• ganaxolone

  quetiapine and ganaxolone both increase sedation. Use Caution/Monitor.

• gemifloxacin

  quetiapine, gemifloxacin. 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.

• gemtuzumab

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

• glimepiride

  quetiapine, 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

  quetiapine, 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

  quetiapine, 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

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

• glycopyrrolate inhaled

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

• grapefruit

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

• griseofulvin

  griseofulvin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• guanfacine

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

• haloperidol

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

• hawthorn

  quetiapine, hawthorn. 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.

• henbane

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

• homatropine

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

• hydrocortisone

  hydrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydromorphone

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

• hydroxyzine

  hydroxyzine and quetiapine both increase sedation. Use Caution/Monitor.

• hyoscyamine

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

• hyoscyamine spray

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

• ibutilide

  quetiapine, ibutilide. 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.

• iloperidone

  iloperidone and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  iloperidone and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, iloperidone. 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.
  
  iloperidone increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

• imipramine

  quetiapine and imipramine both increase sedation. Use Caution/Monitor.

• incobotulinumtoxinA

  quetiapine, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

• indacaterol, inhaled

  indacaterol, inhaled, quetiapine. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.

• indapamide

  quetiapine, indapamide. 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.

• indinavir

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

• insulin aspart

  quetiapine, 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 degludec

  quetiapine 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/insulin aspart

  quetiapine 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

  quetiapine, 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.

• insulin glargine

  quetiapine, 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.

• insulin glulisine

  quetiapine, 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.

• insulin inhaled

  quetiapine 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.

• insulin lispro

  quetiapine, 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 NPH

  quetiapine, 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 regular human

  quetiapine, 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.

• ipratropium

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

• isoniazid

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

• isoproterenol

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

• isradipine

  quetiapine, isradipine. 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.

• istradefylline

  istradefylline will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

• itraconazole

  itraconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor for adverse reactions. Concomitant drug dose reduction may be necessary.

• ketoconazole

  ketoconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one sixth of the original dose when coadministered with a strong CYP3A4 inhibitor.

• ketotifen, ophthalmic

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

• lapatinib

  lapatinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, lapatinib. 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.

• lasmiditan

  lasmiditan, quetiapine. 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, quetiapine. 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.

• lenvatinib

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

• letermovir

  letermovir increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levalbuterol

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

• levofloxacin

  quetiapine, levofloxacin. 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.

• levoketoconazole

  levoketoconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one sixth of the original dose when coadministered with a strong CYP3A4 inhibitor.

• levomilnacipran

  levomilnacipran, quetiapine. 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 quetiapine both increase sedation. Use Caution/Monitor.

• linezolid

  linezolid, quetiapine. 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

  quetiapine, 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

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

• lithium

  lithium, quetiapine. 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).

• lofepramine

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

• lofexidine

  quetiapine and lofexidine both increase sedation. Use Caution/Monitor.
  
  quetiapine and lofexidine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended.

• lopinavir

  quetiapine, lopinavir. 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.

• loprazolam

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

• lorazepam

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

• lorcaserin

  lorcaserin, quetiapine. 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).

• lorlatinib

  lorlatinib will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lormetazepam

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

• loxapine

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

• loxapine inhaled

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

• lumefantrine

  lumefantrine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, lumefantrine. 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.

• lurasidone

  lurasidone, quetiapine. Either increases toxicity of the other by sedation. Use Caution/Monitor. Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• maprotiline

  quetiapine and maprotiline both increase sedation. Use Caution/Monitor.
  
  quetiapine, maprotiline. 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.

• maraviroc

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

• marijuana

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

• meclizine

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

• mefloquine

  quetiapine, mefloquine. 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.

• melatonin

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

• meperidine

  meperidine and quetiapine both increase sedation. Use Caution/Monitor.
  
  meperidine, quetiapine. 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

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

• metaproterenol

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

• metaxalone

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

• metformin

  quetiapine, 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.

• methadone

  methadone and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, methadone. 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.
  
  methadone, quetiapine. 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

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

• methocarbamol

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

• methscopolamine

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

• methylenedioxymethamphetamine

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

• methylergonovine

  methylergonovine, quetiapine. 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

  quetiapine 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.

• methylprednisolone

  methylprednisolone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metoclopramide

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

• metronidazole

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

• miconazole vaginal

  miconazole vaginal will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• midazolam

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

• midazolam intranasal

  midazolam intranasal, quetiapine. 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

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

• mifepristone

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

• miglitol

  quetiapine, 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, quetiapine. 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).

• mirtazapine

  quetiapine and mirtazapine both increase sedation. Use Caution/Monitor.

• mitotane

  mitotane decreases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

• modafinil

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

• morphine

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

• motherwort

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

• moxifloxacin

  quetiapine, moxifloxacin. 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.

• moxonidine

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

• nabilone

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

• nafcillin

  nafcillin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nalbuphine

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

• naratriptan

  naratriptan, quetiapine. 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

  quetiapine, 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.

• nelfinavir

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

• nevirapine

  nevirapine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nifedipine

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

• nilotinib

  nilotinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, nilotinib. 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.

• nirmatrelvir

  nirmatrelvir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one-sixth when coadministered with strong CYP3A4 inhibitors.

• nirmatrelvir/ritonavir

  nirmatrelvir/ritonavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one-sixth when coadministered with strong CYP3A4 inhibitors.

• norepinephrine

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

• nortriptyline

  quetiapine and nortriptyline both increase sedation. Use Caution/Monitor.
  
  quetiapine, nortriptyline. 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.

• octreotide

  quetiapine, octreotide. 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.

• ofloxacin

  quetiapine, ofloxacin. 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

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

• oliceridine

  oliceridine, quetiapine. 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

  quetiapine and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. Drugs that prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmias

• onabotulinumtoxinA

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

• opium tincture

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

• orphenadrine

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

• osilodrostat

  osilodrostat and quetiapine both increase QTc interval. Use Caution/Monitor.

• osimertinib

  osimertinib and quetiapine 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 quetiapine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.

• oxazepam

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

• oxcarbazepine

  oxcarbazepine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxybutynin

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

• oxybutynin topical

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

• oxybutynin transdermal

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

• oxycodone

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

• oxymorphone

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

• ozanimod

  ozanimod and quetiapine 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

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

• pancuronium

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

• papaveretum

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

• papaverine

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

• paroxetine

  paroxetine, quetiapine. 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).

• pasireotide

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

• pazopanib

  quetiapine, pazopanib. 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.

• pentamidine

  quetiapine, pentamidine. 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.

• pentazocine

  pentazocine and quetiapine both increase sedation. Use Caution/Monitor.

• pentobarbital

  pentobarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  pentobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• perphenazine

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

• phendimetrazine

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

• phenelzine

  phenelzine, quetiapine. 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  phenobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• phentermine

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

• phenylephrine

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

• phenylephrine PO

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

• phenytoin

  phenytoin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased doses of quetiapine may be required to maintain control of psychotic symptoms in patients receiving quetiapine and phenytoin. Caution should be taken if phenytoin is withdrawn from therapy or replaced with a non-inducing anticonvulsant.

• pholcodine

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

• pimozide

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

• pioglitazone

  quetiapine, 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.

• pirbuterol

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

• posaconazole

  posaconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, posaconazole. 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.

• pralidoxime

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

• pramlintide

  quetiapine, 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.

• prednisone

  prednisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• primidone

  primidone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  primidone and quetiapine both increase sedation. Use Caution/Monitor.

• procainamide

  quetiapine, procainamide. 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.

• procarbazine

  procarbazine, quetiapine. 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

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

• promethazine

  promethazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  promethazine and quetiapine both increase sedation. Use Caution/Monitor.
  
  promethazine, quetiapine. 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).

• propafenone

  quetiapine, propafenone. 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.

• propantheline

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

• propofol

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

• propylhexedrine

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

• protriptyline

  quetiapine and protriptyline both increase sedation. Use Caution/Monitor.
  
  quetiapine, protriptyline. 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.

• quazepam

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

• quinidine

  quetiapine, quinidine. 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.

• quinine

  quetiapine, quinine. 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.

• quinupristin/dalfopristin

  quinupristin/dalfopristin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ramelteon

  quetiapine and ramelteon both increase sedation. Use Caution/Monitor.

• ranolazine

  quetiapine, ranolazine. 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.

• rapacuronium

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

• remimazolam

  remimazolam, quetiapine. 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

  quetiapine, 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

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

• rifapentine

  rifapentine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rilpivirine

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

• rimabotulinumtoxinB

  quetiapine, 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

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

• ritonavir

  ritonavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, ritonavir. 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.

• rocuronium

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

• romidepsin

  quetiapine, romidepsin. 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.

• rosiglitazone

  quetiapine, 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

• rufinamide

  rufinamide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• salmeterol

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

• saquinavir

  saquinavir increases levels of quetiapine by QTc interval. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Increased risk of QT prolongation and cardiac arrhythmias.
  
  quetiapine, saquinavir. 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.

• scopolamine

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

• scullcap

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

• secobarbital

  secobarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  secobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• selegiline

  selegiline, quetiapine. 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 quetiapine by QTc interval. Use Caution/Monitor.

• shepherd's purse

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

• sitagliptin

  quetiapine, 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.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of quetiapine by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases effects of quetiapine 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 toxicity of quetiapine by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases effects of quetiapine 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.

• solifenacin

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

• sorafenib

  sorafenib and quetiapine both increase QTc interval. Use Caution/Monitor.

• sotalol

  quetiapine, sotalol. 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.

• stiripentol

  stiripentol, quetiapine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
  
  stiripentol, quetiapine. 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 quetiapine both increase sedation. Use Caution/Monitor.

• sumatriptan

  sumatriptan, quetiapine. 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

  sumatriptan intranasal, quetiapine. 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).

• sunitinib

  quetiapine, sunitinib. 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.

• tacrolimus

  quetiapine, tacrolimus. 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.

• tapentadol

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

• tazemetostat

  tazemetostat will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tecovirimat

  tecovirimat will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• telavancin

  quetiapine, telavancin. 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.

• temazepam

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

• terbutaline

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

• tetrabenazine

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

• thioridazine

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

• thiothixene

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

• tiotropium

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

• tipranavir

  tipranavir will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration may increase quetiapine systemic exposure; more frequent monitoring of the clinical response to quetiapine as well as potential adverse events is recommended

• tolazamide

  quetiapine, 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

  quetiapine, 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.

• tolterodine

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

• topiramate

  topiramate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• toremifene

  quetiapine, toremifene. 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.

• tramadol

  tramadol and quetiapine both increase sedation. Use Caution/Monitor.

• tranylcypromine

  tranylcypromine, quetiapine. 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

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

• triazolam

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

• triclabendazole

  triclabendazole and quetiapine both increase QTc interval. Use Caution/Monitor.

• triclofos

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

• trifluoperazine

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

• trihexyphenidyl

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

• trimipramine

  quetiapine and trimipramine both increase sedation. Use Caution/Monitor.
  
  quetiapine, trimipramine. 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.

• triprolidine

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

• trospium chloride

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

• vandetanib

  quetiapine, vandetanib. 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.

• vardenafil

  quetiapine, vardenafil. 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.

• vecuronium

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

• venlafaxine

  venlafaxine, quetiapine. 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vilazodone

  vilazodone, quetiapine. 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, quetiapine. Either increases effects of the other by QTc interval. Use Caution/Monitor.

• voriconazole

  voriconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, voriconazole. 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.

• vorinostat

  quetiapine, vorinostat. 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.

• xylometazoline

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

• yohimbine

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

• zafirlukast

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

• ziconotide

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

• ziprasidone

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

• zolmitriptan

  zolmitriptan, quetiapine. 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).

• zotepine

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

Minor (5)

• brimonidine

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

• chasteberry

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

• ethanol

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

• eucalyptus

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

• sage

  quetiapine and sage both increase sedation. Minor/Significance Unknown.

• abametapir

  Serious - Use Alternative (1)abametapir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

• abobotulinumtoxinA

  Monitor Closely (1)abobotulinumtoxinA increases effects of quetiapine 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)quetiapine, 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.

• aclidinium

  Monitor Closely (2)aclidinium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• albiglutide

  Monitor Closely (1)quetiapine, 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 (2)quetiapine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  albuterol and quetiapine both increase QTc interval. Use Caution/Monitor.

• alfentanil

  Monitor Closely (1)alfentanil and quetiapine both increase sedation. Use Caution/Monitor.

• alfuzosin

  Monitor Closely (1)quetiapine and alfuzosin both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)alfuzosin and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• almotriptan

  Monitor Closely (1)almotriptan, quetiapine. 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).

• alprazolam

  Monitor Closely (1)alprazolam and quetiapine both increase sedation. Use Caution/Monitor.

• amifostine

  Monitor Closely (1)amifostine, quetiapine. 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)quetiapine, amiodarone. 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.

• amisulpride

  Contraindicated (1)amisulpride, quetiapine. 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 (1)amisulpride and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.

• amitriptyline

  Monitor Closely (2)quetiapine and amitriptyline both increase sedation. Use Caution/Monitor.
  
  quetiapine, amitriptyline. 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.

• amobarbital

  Monitor Closely (2)amobarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  amobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• amoxapine

  Monitor Closely (3)quetiapine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and amoxapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, amoxapine. 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.

• anticholinergic/sedative combos

  Monitor Closely (3)anticholinergic/sedative combos decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  anticholinergic/sedative combos decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• apalutamide

  Serious - Use Alternative (1)apalutamide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

• apomorphine

  Monitor Closely (2)quetiapine and apomorphine both increase sedation. Use Caution/Monitor.
  
  quetiapine, apomorphine. 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.Serious - Use Alternative (1)quetiapine decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• aprepitant

  Monitor Closely (1)aprepitant will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• arformoterol

  Monitor Closely (2)quetiapine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  arformoterol and quetiapine both increase QTc interval. Use Caution/Monitor.

• aripiprazole

  Monitor Closely (2)aripiprazole and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  aripiprazole and quetiapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)aripiprazole and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• armodafinil

  Monitor Closely (2)armodafinil will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• arsenic trioxide

  Monitor Closely (1)quetiapine, arsenic trioxide. 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.

• artemether

  Serious - Use Alternative (1)artemether and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• artemether/lumefantrine

  Monitor Closely (2)artemether/lumefantrine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, artemether/lumefantrine. 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.

• asenapine

  Monitor Closely (1)quetiapine, asenapine. 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.

• atazanavir

  Serious - Use Alternative (1)atazanavir increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternative anti-HCV therapy to avoid increases in quetiapine exposures; if coadministration is necessary, reduce quetiapine dose to 1/6th of current dose and monitor for quetiapine associated adverse reactions; refer to quetiapine prescribing information for recommendations on adverse reaction monitoring.

• atomoxetine

  Serious - Use Alternative (1)atomoxetine and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• atracurium

  Monitor Closely (3)atracurium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atracurium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• atropine

  Monitor Closely (3)atropine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• atropine IV/IM

  Monitor Closely (3)quetiapine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  atropine IV/IM decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine IV/IM decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.

• azelastine

  Monitor Closely (1)azelastine and quetiapine both increase sedation. Use Caution/Monitor.

• azithromycin

  Monitor Closely (1)quetiapine, azithromycin. 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.

• baclofen

  Monitor Closely (1)baclofen and quetiapine both increase sedation. Use Caution/Monitor.

• bedaquiline

  Monitor Closely (1)quetiapine 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 quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  belladonna alkaloids decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine 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 quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  belladonna and opium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  belladonna and opium and quetiapine both increase sedation. Use Caution/Monitor.

• benazepril

  Monitor Closely (2)benazepril increases toxicity of quetiapine by pharmacodynamic synergism. Use Caution/Monitor. Increases risk of hypotension.
  
  quetiapine increases toxicity of benazepril by pharmacodynamic synergism. Use Caution/Monitor. Increases risk of hypotension.

• benperidol

  Monitor Closely (2)benperidol and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  benperidol and quetiapine both increase sedation. Use Caution/Monitor.

• benzhydrocodone/acetaminophen

  Serious - Use Alternative (1)benzhydrocodone/acetaminophen, quetiapine. 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)quetiapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• benztropine

  Monitor Closely (1)quetiapine increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .

• bosentan

  Monitor Closely (1)bosentan will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexanolone

  Monitor Closely (1)brexanolone, quetiapine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brimonidine

  Minor (1)brimonidine increases effects of quetiapine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

• bromocriptine

  Serious - Use Alternative (1)quetiapine decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• brompheniramine

  Monitor Closely (1)brompheniramine and quetiapine both increase sedation. Use Caution/Monitor.

• budesonide

  Monitor Closely (1)budesonide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine

  Monitor Closely (1)buprenorphine and quetiapine both increase sedation. Use Caution/Monitor.

• buprenorphine buccal

  Monitor Closely (1)buprenorphine buccal and quetiapine both increase sedation. Use Caution/Monitor.

• buprenorphine, long-acting injection

  Monitor Closely (1)quetiapine 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.

• butabarbital

  Monitor Closely (2)butabarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  butabarbital and quetiapine both increase sedation. Use Caution/Monitor.

• butalbital

  Monitor Closely (2)butalbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  butalbital and quetiapine both increase sedation. Use Caution/Monitor.

• butorphanol

  Monitor Closely (1)butorphanol and quetiapine both increase sedation. Use Caution/Monitor.

• cabergoline

  Serious - Use Alternative (1)quetiapine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

• caffeine

  Monitor Closely (1)quetiapine 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)quetiapine, 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.

• captopril

  Monitor Closely (1)quetiapine, captopril. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure. Monitor blood pressure.

• carbamazepine

  Monitor Closely (1)quetiapine will increase the level or effect of carbamazepine by decreasing metabolism. Modify Therapy/Monitor Closely. Monitor plasma levels when used concomitantlySerious - Use Alternative (1)carbamazepine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• carbinoxamine

  Monitor Closely (1)carbinoxamine and quetiapine both increase sedation. Use Caution/Monitor.

• carisoprodol

  Monitor Closely (1)carisoprodol and quetiapine both increase sedation. Use Caution/Monitor.

• cenobamate

  Monitor Closely (2)cenobamate, quetiapine. Either increases effects of the other by sedation. Use Caution/Monitor.
  
  cenobamate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

• ceritinib

  Serious - Use Alternative (1)ceritinib and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• chasteberry

  Minor (1)chasteberry decreases effects of quetiapine by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).

• chloral hydrate

  Monitor Closely (1)chloral hydrate and quetiapine both increase sedation. Use Caution/Monitor.

• chloramphenicol

  Serious - Use Alternative (1)chloramphenicol will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• chlordiazepoxide

  Monitor Closely (1)chlordiazepoxide and quetiapine both increase sedation. Use Caution/Monitor.

• chloroquine

  Monitor Closely (1)chloroquine increases toxicity of quetiapine by QTc interval. Use Caution/Monitor.

• chlorpheniramine

  Monitor Closely (1)chlorpheniramine and quetiapine both increase sedation. Use Caution/Monitor.

• chlorpromazine

  Monitor Closely (3)chlorpromazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  chlorpromazine and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, chlorpromazine. 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.

• chlorpropamide

  Monitor Closely (1)quetiapine, 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 quetiapine both increase sedation. Use Caution/Monitor.

• cimetidine

  Serious - Use Alternative (1)cimetidine will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cinnarizine

  Monitor Closely (1)cinnarizine and quetiapine both increase sedation. Use Caution/Monitor.

• ciprofloxacin

  Monitor Closely (1)quetiapine, ciprofloxacin. 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.

• cisatracurium

  Monitor Closely (3)cisatracurium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cisatracurium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• citalopram

  Monitor Closely (1)quetiapine, citalopram. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT interval 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. ECG monitoring is recommended.

• clarithromycin

  Monitor Closely (1)quetiapine, clarithromycin. 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.Serious - Use Alternative (1)clarithromycin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• clemastine

  Monitor Closely (1)clemastine and quetiapine both increase sedation. Use Caution/Monitor.

• clobazam

  Monitor Closely (1)quetiapine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

• clomipramine

  Monitor Closely (2)quetiapine and clomipramine both increase sedation. Use Caution/Monitor.
  
  quetiapine, clomipramine. 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.

• clonazepam

  Monitor Closely (1)clonazepam and quetiapine both increase sedation. Use Caution/Monitor.

• clonidine

  Monitor Closely (1)clonidine, quetiapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

• clorazepate

  Monitor Closely (1)clorazepate and quetiapine both increase sedation. Use Caution/Monitor.

• clozapine

  Monitor Closely (2)clozapine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  clozapine and quetiapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)clozapine and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• cobicistat

  Serious - Use Alternative (1)cobicistat increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with atazanavir and cobicistat in patients taking quetiapine. If coadministration is necessary, reduce quetiapine dose to one-sixth of the current dose and monitor for quetiapine-associated adverse reactions. Refer to quetiapine prescribing information for initial dosing and titration of quetiapine.

• codeine

  Monitor Closely (1)codeine and quetiapine both increase sedation. Use Caution/Monitor.

• conivaptan

  Monitor Closely (1)conivaptan will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cortisone

  Monitor Closely (1)cortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• crizotinib

  Monitor Closely (1)crizotinib increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A. ECG monitoring is recommended, along with drugs that may prolong the QT interval.Serious - Use Alternative (1)crizotinib and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• crofelemer

  Monitor Closely (1)crofelemer increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

• cyclizine

  Monitor Closely (4)cyclizine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cyclizine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of cyclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  cyclizine and quetiapine both increase sedation. Use Caution/Monitor.

• cyclobenzaprine

  Monitor Closely (5)cyclobenzaprine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cyclobenzaprine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of cyclobenzaprine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  cyclobenzaprine and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, cyclobenzaprine. 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.

• cyclosporine

  Monitor Closely (1)cyclosporine will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cyproheptadine

  Monitor Closely (1)cyproheptadine and quetiapine both increase sedation. Use Caution/Monitor.

• dabrafenib

  Serious - Use Alternative (1)dabrafenib will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dantrolene

  Monitor Closely (1)dantrolene and quetiapine both increase sedation. Use Caution/Monitor.

• daridorexant

  Monitor Closely (1)quetiapine 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 (4)darifenacin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  darifenacin decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  darifenacin decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• darunavir

  Monitor Closely (1)darunavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dasatinib

  Monitor Closely (2)dasatinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, dasatinib. 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.

• deferasirox

  Monitor Closely (1)deferasirox will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• degarelix

  Monitor Closely (1)quetiapine, degarelix. 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.

• desflurane

  Monitor Closely (1)desflurane and quetiapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)desflurane and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• desipramine

  Monitor Closely (2)quetiapine and desipramine both increase sedation. Use Caution/Monitor.
  
  quetiapine, desipramine. 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.

• deutetrabenazine

  Monitor Closely (3)quetiapine and deutetrabenazine both increase sedation. Use Caution/Monitor.
  
  quetiapine 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.
  
  quetiapine and deutetrabenazine both increase QTc interval. Modify Therapy/Monitor Closely. For patients requiring deutetrabenazine doses >24 mg/day and are taking other drugs known to prolong QTc, assess the QTc interval before and after increasing the dose of deutetrabenazine or other medications known to prolong QTc.

• dexamethasone

  Monitor Closely (1)dexamethasone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dexchlorpheniramine

  Monitor Closely (1)dexchlorpheniramine and quetiapine both increase sedation. Use Caution/Monitor.

• dexfenfluramine

  Monitor Closely (1)quetiapine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dexmedetomidine

  Monitor Closely (1)dexmedetomidine and quetiapine both increase sedation. Use Caution/Monitor.

• dexmethylphenidate

  Monitor Closely (1)quetiapine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextroamphetamine

  Monitor Closely (1)quetiapine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextromethorphan

  Monitor Closely (1)dextromethorphan, quetiapine. 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

  Monitor Closely (1)dextromoramide and quetiapine both increase sedation. Use Caution/Monitor.

• DHEA, herbal

  Monitor Closely (1)DHEA, herbal will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diamorphine

  Monitor Closely (1)diamorphine and quetiapine both increase sedation. Use Caution/Monitor.

• diazepam

  Monitor Closely (1)diazepam and quetiapine both increase sedation. Use Caution/Monitor.

• dichlorphenamide

  Monitor Closely (1)dichlorphenamide and quetiapine both decrease serum potassium. Use Caution/Monitor.

• dicyclomine

  Monitor Closely (3)dicyclomine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  dicyclomine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• diethylpropion

  Monitor Closely (1)quetiapine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• difelikefalin

  Monitor Closely (1)difelikefalin and quetiapine both increase sedation. Use Caution/Monitor.

• difenoxin hcl

  Monitor Closely (1)difenoxin hcl and quetiapine both increase sedation. Use Caution/Monitor.

• dihydroergotamine

  Monitor Closely (1)dihydroergotamine, quetiapine. 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).

• diltiazem

  Monitor Closely (1)diltiazem will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dimenhydrinate

  Monitor Closely (1)dimenhydrinate and quetiapine both increase sedation. Use Caution/Monitor.

• diphenhydramine

  Monitor Closely (4)diphenhydramine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  diphenhydramine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  diphenhydramine and quetiapine both increase sedation. Use Caution/Monitor.

• diphenoxylate hcl

  Monitor Closely (1)diphenoxylate hcl and quetiapine both increase sedation. Use Caution/Monitor.

• dipipanone

  Monitor Closely (1)dipipanone and quetiapine both increase sedation. Use Caution/Monitor.

• disopyramide

  Monitor Closely (1)quetiapine, disopyramide. 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.

• dobutamine

  Monitor Closely (1)quetiapine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dofetilide

  Monitor Closely (2)quetiapine, dofetilide. 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.
  
  dofetilide increases toxicity of quetiapine by QTc interval. Use Caution/Monitor.

• dolasetron

  Monitor Closely (1)quetiapine, dolasetron. 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.

• donepezil

  Serious - Use Alternative (1)donepezil and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• donepezil transdermal

  Monitor Closely (1)quetiapine, donepezil transdermal. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.

• dopamine

  Monitor Closely (1)quetiapine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)quetiapine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

• dopexamine

  Monitor Closely (1)quetiapine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dosulepin

  Monitor Closely (1)quetiapine and dosulepin both increase sedation. Use Caution/Monitor.

• doxepin

  Monitor Closely (2)quetiapine and doxepin both increase sedation. Use Caution/Monitor.
  
  doxepin and quetiapine both increase QTc interval. Use Caution/Monitor.

• doxylamine

  Monitor Closely (1)doxylamine and quetiapine both increase sedation. Use Caution/Monitor.

• dronedarone

  Monitor Closely (2)dronedarone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, dronedarone. 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.

• droperidol

  Monitor Closely (3)droperidol and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  droperidol and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, droperidol. 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.

• duvelisib

  Monitor Closely (1)duvelisib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.

• efavirenz

  Monitor Closely (1)efavirenz will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• elagolix

  Monitor Closely (1)elagolix decreases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

• eletriptan

  Monitor Closely (1)eletriptan, quetiapine. 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).

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Serious - Use Alternative (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with quetiapine. If coadministration is necessary, reduce quetiapine dose to one-sixth of the current dose.

• encorafenib

  Monitor Closely (1)encorafenib, quetiapine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.Serious - Use Alternative (1)encorafenib and quetiapine 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.

• entrectinib

  Serious - Use Alternative (1)quetiapine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.

• enzalutamide

  Serious - Use Alternative (1)enzalutamide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ephedrine

  Monitor Closely (1)quetiapine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine

  Monitor Closely (1)quetiapine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine racemic

  Monitor Closely (1)quetiapine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ergoloid mesylates

  Monitor Closely (1)ergoloid mesylates, quetiapine. 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 (1)ergotamine, quetiapine. 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

  Serious - Use Alternative (1)eribulin and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin base

  Monitor Closely (1)quetiapine, erythromycin base. 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.Serious - Use Alternative (1)erythromycin base will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Monitor Closely (1)quetiapine, erythromycin ethylsuccinate. 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.Serious - Use Alternative (1)erythromycin ethylsuccinate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Monitor Closely (1)quetiapine, erythromycin lactobionate. 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.Serious - Use Alternative (1)erythromycin lactobionate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  Monitor Closely (1)quetiapine, erythromycin stearate. 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.Serious - Use Alternative (1)erythromycin stearate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• escitalopram

  Monitor Closely (1)quetiapine, escitalopram. 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.Serious - Use Alternative (1)escitalopram increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug.

• esketamine intranasal

  Monitor Closely (1)esketamine intranasal, quetiapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• eslicarbazepine acetate

  Monitor Closely (1)eslicarbazepine acetate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estazolam

  Monitor Closely (1)estazolam and quetiapine both increase sedation. Use Caution/Monitor.

• ethanol

  Monitor Closely (1)quetiapine and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol, quetiapine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.

• etravirine

  Monitor Closely (1)etravirine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• eucalyptus

  Minor (1)quetiapine and eucalyptus both increase sedation. Minor/Significance Unknown.

• exenatide injectable solution

  Monitor Closely (1)quetiapine, 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)quetiapine, 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, quetiapine. Either increases toxicity of the other by 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

• fenfluramine

  Monitor Closely (2)quetiapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
  
  quetiapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• fentanyl

  Monitor Closely (1)fentanyl, quetiapine. 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

  Monitor Closely (3)fesoterodine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  fesoterodine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• fexinidazole

  Serious - Use Alternative (2)fexinidazole and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels and/or prolong QT interval.
  
  fexinidazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

• fingolimod

  Serious - Use Alternative (1)fingolimod and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• flavoxate

  Monitor Closely (3)flavoxate decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  flavoxate decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• flecainide

  Monitor Closely (1)quetiapine, flecainide. 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.

• flibanserin

  Monitor Closely (1)flibanserin, quetiapine. 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).

• fluconazole

  Monitor Closely (2)fluconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, fluconazole. 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.

• fludrocortisone

  Monitor Closely (1)fludrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fluoxetine

  Monitor Closely (1)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.

• fluphenazine

  Monitor Closely (2)fluphenazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and quetiapine both increase sedation. Use Caution/Monitor.

• flurazepam

  Monitor Closely (1)flurazepam and quetiapine both increase sedation. Use Caution/Monitor.

• fluvoxamine

  Monitor Closely (1)fluvoxamine will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• formoterol

  Monitor Closely (1)quetiapine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• fosamprenavir

  Monitor Closely (1)fosamprenavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• foscarnet

  Monitor Closely (1)quetiapine, foscarnet. 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.

• fosphenytoin

  Monitor Closely (1)fosphenytoin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fostemsavir

  Monitor Closely (1)quetiapine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

• frovatriptan

  Monitor Closely (1)frovatriptan, quetiapine. 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).

• gadobenate

  Monitor Closely (1)gadobenate and quetiapine both increase QTc interval. Use Caution/Monitor.

• ganaxolone

  Monitor Closely (1)quetiapine and ganaxolone both increase sedation. Use Caution/Monitor.

• gemifloxacin

  Monitor Closely (1)quetiapine, gemifloxacin. 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.

• gemtuzumab

  Monitor Closely (1)quetiapine and gemtuzumab both increase QTc interval. Use Caution/Monitor.

• gilteritinib

  Serious - Use Alternative (1)gilteritinib and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• glasdegib

  Serious - Use Alternative (1)quetiapine 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 (1)quetiapine, 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 (1)quetiapine, 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 (1)quetiapine, 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)quetiapine 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 quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  glycopyrrolate inhaled decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• goserelin

  Contraindicated (1)goserelin increases toxicity of quetiapine by QTc interval. Contraindicated. Increases risk of torsades de pointes.

• granisetron

  Serious - Use Alternative (1)granisetron and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• grapefruit

  Monitor Closely (1)grapefruit will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• griseofulvin

  Monitor Closely (1)griseofulvin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• guanfacine

  Monitor Closely (1)guanfacine, quetiapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

• haloperidol

  Monitor Closely (3)haloperidol and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  haloperidol and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, haloperidol. 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.

• hawthorn

  Monitor Closely (1)quetiapine, hawthorn. 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.

• henbane

  Monitor Closely (3)henbane decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  henbane decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• histrelin

  Serious - Use Alternative (1)histrelin increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• homatropine

  Monitor Closely (3)homatropine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  homatropine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hydrocodone

  Serious - Use Alternative (1)hydrocodone, quetiapine. 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.

• hydrocortisone

  Monitor Closely (1)hydrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydromorphone

  Monitor Closely (1)hydromorphone and quetiapine both increase sedation. Use Caution/Monitor.

• hydroxychloroquine sulfate

  Serious - Use Alternative (1)hydroxychloroquine sulfate and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• hydroxyzine

  Monitor Closely (1)hydroxyzine and quetiapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)hydroxyzine increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• hyoscyamine

  Monitor Closely (3)hyoscyamine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  hyoscyamine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• hyoscyamine spray

  Monitor Closely (3)quetiapine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  hyoscyamine spray decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  hyoscyamine spray decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.

• ibutilide

  Monitor Closely (1)quetiapine, ibutilide. 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.

• idelalisib

  Serious - Use Alternative (1)idelalisib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• iloperidone

  Monitor Closely (4)iloperidone and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  iloperidone and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, iloperidone. 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.
  
  iloperidone increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

• imipramine

  Monitor Closely (1)quetiapine and imipramine both increase sedation. Use Caution/Monitor.

• incobotulinumtoxinA

  Monitor Closely (1)quetiapine, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

• indacaterol, inhaled

  Monitor Closely (1)indacaterol, inhaled, quetiapine. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.

• indapamide

  Monitor Closely (1)quetiapine, indapamide. 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.

• indinavir

  Monitor Closely (1)indinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• inotuzumab

  Serious - Use Alternative (1)inotuzumab and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. If unable to avoid concomitant use, obtain ECGs and electrolytes before and after initiation of any drug known to prolong QTc, and periodically monitor as clinically indicated during treatment.

• insulin aspart

  Monitor Closely (1)quetiapine, 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 degludec

  Monitor Closely (1)quetiapine 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/insulin aspart

  Monitor Closely (1)quetiapine 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 (1)quetiapine, 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.

• insulin glargine

  Monitor Closely (1)quetiapine, 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.

• insulin glulisine

  Monitor Closely (1)quetiapine, 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.

• insulin inhaled

  Monitor Closely (1)quetiapine 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.

• insulin lispro

  Monitor Closely (1)quetiapine, 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 NPH

  Monitor Closely (1)quetiapine, 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 regular human

  Monitor Closely (1)quetiapine, 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.

• ipratropium

  Monitor Closely (3)ipratropium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  ipratropium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• isoflurane

  Serious - Use Alternative (1)isoflurane and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• isoniazid

  Monitor Closely (1)isoniazid will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isoproterenol

  Monitor Closely (1)quetiapine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• isradipine

  Monitor Closely (1)quetiapine, isradipine. 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.

• istradefylline

  Monitor Closely (1)istradefylline will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

• itraconazole

  Monitor Closely (1)itraconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor for adverse reactions. Concomitant drug dose reduction may be necessary.Serious - Use Alternative (1)itraconazole and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• ivosidenib

  Serious - Use Alternative (2)ivosidenib and quetiapine 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• ketoconazole

  Monitor Closely (1)ketoconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one sixth of the original dose when coadministered with a strong CYP3A4 inhibitor.

• ketotifen, ophthalmic

  Monitor Closely (1)quetiapine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

• lapatinib

  Monitor Closely (2)lapatinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, lapatinib. 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.

• lasmiditan

  Monitor Closely (1)lasmiditan, quetiapine. 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

  Contraindicated (1)lefamulin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.

• lemborexant

  Monitor Closely (1)lemborexant, quetiapine. 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.

• lenvatinib

  Monitor Closely (1)quetiapine and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.

• letermovir

  Monitor Closely (1)letermovir increases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• leuprolide

  Contraindicated (1)leuprolide increases toxicity of quetiapine by QTc interval. Contraindicated. Increases risk of torsades de pointes.

• levalbuterol

  Monitor Closely (1)quetiapine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• levodopa

  Serious - Use Alternative (1)quetiapine decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• levodopa inhaled

  Serious - Use Alternative (1)quetiapine 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 (1)quetiapine, levofloxacin. 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.

• levoketoconazole

  Monitor Closely (1)levoketoconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one sixth of the original dose when coadministered with a strong CYP3A4 inhibitor.

• levomilnacipran

  Monitor Closely (1)levomilnacipran, quetiapine. 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

  Monitor Closely (1)levorphanol and quetiapine both increase sedation. Use Caution/Monitor.

• linezolid

  Monitor Closely (1)linezolid, quetiapine. 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)quetiapine, 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 (1)quetiapine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lisuride

  Serious - Use Alternative (1)quetiapine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

• lithium

  Monitor Closely (1)lithium, quetiapine. 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)lithium and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• lofepramine

  Monitor Closely (1)quetiapine and lofepramine both increase sedation. Use Caution/Monitor.

• lofexidine

  Monitor Closely (2)quetiapine and lofexidine both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended.
  
  quetiapine and lofexidine both increase sedation. Use Caution/Monitor.

• lonafarnib

  Serious - Use Alternative (1)lonafarnib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.

• lopinavir

  Monitor Closely (1)quetiapine, lopinavir. 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.Serious - Use Alternative (1)lopinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• loprazolam

  Monitor Closely (1)loprazolam and quetiapine both increase sedation. Use Caution/Monitor.

• lorazepam

  Monitor Closely (1)lorazepam and quetiapine both increase sedation. Use Caution/Monitor.

• lorcaserin

  Monitor Closely (1)lorcaserin, quetiapine. 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).

• lorlatinib

  Monitor Closely (1)lorlatinib will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lormetazepam

  Monitor Closely (1)lormetazepam and quetiapine both increase sedation. Use Caution/Monitor.

• loxapine

  Monitor Closely (2)loxapine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  loxapine and quetiapine both increase sedation. Use Caution/Monitor.

• loxapine inhaled

  Monitor Closely (2)loxapine inhaled and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  loxapine inhaled and quetiapine both increase sedation. Use Caution/Monitor.

• lumefantrine

  Monitor Closely (2)lumefantrine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, lumefantrine. 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.

• lurasidone

  Monitor Closely (1)lurasidone, quetiapine. Either increases toxicity of the other by sedation. Use Caution/Monitor. Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• macimorelin

  Serious - Use Alternative (1)macimorelin and quetiapine 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)quetiapine and maprotiline both increase sedation. Use Caution/Monitor.
  
  quetiapine, maprotiline. 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.

• maraviroc

  Monitor Closely (1)maraviroc, quetiapine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.

• marijuana

  Monitor Closely (2)marijuana will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine and marijuana both increase sedation. Use Caution/Monitor.

• meclizine

  Monitor Closely (3)meclizine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  meclizine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• mefloquine

  Monitor Closely (1)quetiapine, mefloquine. 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.Serious - Use Alternative (1)mefloquine increases toxicity of quetiapine 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)quetiapine and melatonin both increase sedation. Use Caution/Monitor.

• meperidine

  Monitor Closely (2)meperidine, quetiapine. 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).
  
  meperidine and quetiapine both increase sedation. Use Caution/Monitor.

• meprobamate

  Monitor Closely (1)quetiapine and meprobamate both increase sedation. Use Caution/Monitor.

• metaproterenol

  Monitor Closely (1)quetiapine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metaxalone

  Monitor Closely (1)metaxalone and quetiapine both increase sedation. Use Caution/Monitor.

• metformin

  Monitor Closely (1)quetiapine, 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.

• methadone

  Monitor Closely (3)methadone, quetiapine. 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).
  
  methadone and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, methadone. 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.

• methamphetamine

  Monitor Closely (1)quetiapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methocarbamol

  Monitor Closely (1)methocarbamol and quetiapine both increase sedation. Use Caution/Monitor.

• methscopolamine

  Monitor Closely (3)methscopolamine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  methscopolamine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• methyldopa

  Serious - Use Alternative (1)quetiapine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

• methylenedioxymethamphetamine

  Monitor Closely (1)quetiapine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methylergonovine

  Monitor Closely (1)methylergonovine, quetiapine. 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)quetiapine 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.

• methylprednisolone

  Monitor Closely (1)methylprednisolone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metoclopramide

  Monitor Closely (1)quetiapine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

• metoclopramide intranasal

  Serious - Use Alternative (2)quetiapine, 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.
  
  quetiapine 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.

• metronidazole

  Monitor Closely (1)metronidazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• miconazole vaginal

  Monitor Closely (1)miconazole vaginal will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• midazolam

  Monitor Closely (1)midazolam and quetiapine both increase sedation. Use Caution/Monitor.

• midazolam intranasal

  Monitor Closely (1)midazolam intranasal, quetiapine. 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)quetiapine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mifepristone

  Monitor Closely (1)mifepristone, quetiapine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.Serious - Use Alternative (1)mifepristone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• miglitol

  Monitor Closely (1)quetiapine, 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, quetiapine. 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).

• mirtazapine

  Monitor Closely (1)quetiapine and mirtazapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)mirtazapine and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• mitotane

  Monitor Closely (1)mitotane decreases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

• mobocertinib

  Serious - Use Alternative (1)mobocertinib and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.

• modafinil

  Monitor Closely (1)quetiapine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• morphine

  Monitor Closely (1)morphine and quetiapine both increase sedation. Use Caution/Monitor.

• motherwort

  Monitor Closely (1)quetiapine and motherwort both increase sedation. Use Caution/Monitor.

• moxifloxacin

  Monitor Closely (1)quetiapine, moxifloxacin. 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.

• moxonidine

  Monitor Closely (1)quetiapine and moxonidine both increase sedation. Use Caution/Monitor.

• nabilone

  Monitor Closely (1)quetiapine and nabilone both increase sedation. Use Caution/Monitor.

• nafcillin

  Monitor Closely (1)nafcillin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nalbuphine

  Monitor Closely (1)nalbuphine and quetiapine both increase sedation. Use Caution/Monitor.

• naratriptan

  Monitor Closely (1)naratriptan, quetiapine. 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

  Monitor Closely (1)quetiapine, 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.

• nefazodone

  Serious - Use Alternative (1)nefazodone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nelfinavir

  Monitor Closely (1)nelfinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nevirapine

  Monitor Closely (1)nevirapine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nifedipine

  Monitor Closely (1)nifedipine will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nilotinib

  Monitor Closely (2)nilotinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, nilotinib. 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.

• nirmatrelvir

  Monitor Closely (1)nirmatrelvir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one-sixth when coadministered with strong CYP3A4 inhibitors.

• nirmatrelvir/ritonavir

  Monitor Closely (1)nirmatrelvir/ritonavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce quetiapine dose to one-sixth when coadministered with strong CYP3A4 inhibitors.

• norepinephrine

  Monitor Closely (1)quetiapine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nortriptyline

  Monitor Closely (2)quetiapine and nortriptyline both increase sedation. Use Caution/Monitor.
  
  quetiapine, nortriptyline. 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.

• octreotide

  Monitor Closely (1)quetiapine, octreotide. 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.

• ofloxacin

  Monitor Closely (1)quetiapine, ofloxacin. 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

  Monitor Closely (2)olanzapine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  olanzapine and quetiapine both increase sedation. Use Caution/Monitor.

• oliceridine

  Monitor Closely (1)oliceridine, quetiapine. 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)quetiapine and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. Drugs that prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmias

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  Serious - Use Alternative (1)ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternative anti-HCV therapy to avoid increases in quetiapine exposures; if coadministration necessary, reduce quetiapine dose to 1/6th of current dose and monitor for quetiapine associated adverse reactions; refer to quetiapine prescribing information for recommendations on adverse reaction monitoring

• onabotulinumtoxinA

  Monitor Closely (3)onabotulinumtoxinA decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  onabotulinumtoxinA decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• ondansetron

  Serious - Use Alternative (1)quetiapine 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 quetiapine both increase sedation. Use Caution/Monitor.

• orphenadrine

  Monitor Closely (1)orphenadrine and quetiapine both increase sedation. Use Caution/Monitor.

• osilodrostat

  Monitor Closely (1)osilodrostat and quetiapine both increase QTc interval. Use Caution/Monitor.

• osimertinib

  Monitor Closely (1)osimertinib and quetiapine 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 quetiapine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.

• oxazepam

  Monitor Closely (1)oxazepam and quetiapine both increase sedation. Use Caution/Monitor.

• oxcarbazepine

  Monitor Closely (1)oxcarbazepine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxybutynin

  Monitor Closely (3)oxybutynin decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine 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 quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin topical decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine 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 quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin transdermal decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• oxycodone

  Monitor Closely (1)oxycodone and quetiapine both increase sedation. Use Caution/Monitor.

• oxymorphone

  Monitor Closely (1)oxymorphone and quetiapine both increase sedation. Use Caution/Monitor.

• ozanimod

  Monitor Closely (1)ozanimod and quetiapine 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

  Monitor Closely (3)paliperidone and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  paliperidone and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, paliperidone. 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.

• pancuronium

  Monitor Closely (3)pancuronium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  pancuronium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• panobinostat

  Serious - Use Alternative (1)quetiapine 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.

• papaveretum

  Monitor Closely (1)papaveretum and quetiapine both increase sedation. Use Caution/Monitor.

• papaverine

  Monitor Closely (1)quetiapine and papaverine both increase sedation. Use Caution/Monitor.

• paroxetine

  Monitor Closely (1)paroxetine, quetiapine. 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).

• pasireotide

  Monitor Closely (1)quetiapine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.

• pazopanib

  Monitor Closely (1)quetiapine, pazopanib. 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.

• pentamidine

  Monitor Closely (1)quetiapine, pentamidine. 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.

• pentazocine

  Monitor Closely (1)pentazocine and quetiapine both increase sedation. Use Caution/Monitor.

• pentobarbital

  Monitor Closely (2)pentobarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  pentobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• perphenazine

  Monitor Closely (2)perphenazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  perphenazine and quetiapine both increase sedation. Use Caution/Monitor.

• phendimetrazine

  Monitor Closely (1)quetiapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenelzine

  Monitor Closely (1)phenelzine, quetiapine. 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 quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  phenobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• phentermine

  Monitor Closely (1)quetiapine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine

  Monitor Closely (1)quetiapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine PO

  Monitor Closely (1)quetiapine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• phenytoin

  Monitor Closely (1)phenytoin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased doses of quetiapine may be required to maintain control of psychotic symptoms in patients receiving quetiapine and phenytoin. Caution should be taken if phenytoin is withdrawn from therapy or replaced with a non-inducing anticonvulsant.

• pholcodine

  Monitor Closely (1)quetiapine and pholcodine both increase sedation. Use Caution/Monitor.

• pimavanserin

  Serious - Use Alternative (1)pimavanserin and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.

• pimozide

  Monitor Closely (3)pimozide and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  pimozide and quetiapine both increase sedation. Use Caution/Monitor.
  
  quetiapine, pimozide. 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.

• pioglitazone

  Monitor Closely (1)quetiapine, 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.

• pirbuterol

  Monitor Closely (1)quetiapine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• pitolisant

  Serious - Use Alternative (1)quetiapine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.

• posaconazole

  Monitor Closely (2)posaconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, posaconazole. 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.

• pralidoxime

  Monitor Closely (3)pralidoxime decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  pralidoxime decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• pramipexole

  Serious - Use Alternative (1)quetiapine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

• pramlintide

  Monitor Closely (1)quetiapine, 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.

• prednisone

  Monitor Closely (1)prednisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• primidone

  Monitor Closely (2)primidone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  primidone and quetiapine both increase sedation. Use Caution/Monitor.

• procainamide

  Monitor Closely (1)quetiapine, procainamide. 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.

• procarbazine

  Monitor Closely (1)procarbazine, quetiapine. 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 (2)prochlorperazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  prochlorperazine and quetiapine both increase sedation. Use Caution/Monitor.

• promethazine

  Monitor Closely (3)promethazine, quetiapine. 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).
  
  promethazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  promethazine and quetiapine both increase sedation. Use Caution/Monitor.

• propafenone

  Monitor Closely (1)quetiapine, propafenone. 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.

• propantheline

  Monitor Closely (3)propantheline decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  propantheline decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• propofol

  Monitor Closely (1)propofol and quetiapine both increase sedation. Use Caution/Monitor.

• propylhexedrine

  Monitor Closely (1)quetiapine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• protriptyline

  Monitor Closely (2)quetiapine and protriptyline both increase sedation. Use Caution/Monitor.
  
  quetiapine, protriptyline. 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.

• quazepam

  Monitor Closely (1)quazepam and quetiapine both increase sedation. Use Caution/Monitor.

• quinidine

  Monitor Closely (1)quetiapine, quinidine. 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.

• quinine

  Monitor Closely (1)quetiapine, quinine. 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.

• quinupristin/dalfopristin

  Monitor Closely (1)quinupristin/dalfopristin will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ramelteon

  Monitor Closely (1)quetiapine and ramelteon both increase sedation. Use Caution/Monitor.

• ranolazine

  Monitor Closely (1)quetiapine, ranolazine. 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.

• rapacuronium

  Monitor Closely (3)rapacuronium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  rapacuronium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• remimazolam

  Monitor Closely (1)remimazolam, quetiapine. 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)quetiapine, 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

  Monitor Closely (1)ribociclib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)ribociclib and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• rifabutin

  Serious - Use Alternative (1)rifabutin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rifampin

  Serious - Use Alternative (1)rifampin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rifapentine

  Monitor Closely (1)rifapentine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rilpivirine

  Monitor Closely (1)rilpivirine increases toxicity of quetiapine by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsade de Pointes.

• rimabotulinumtoxinB

  Monitor Closely (1)quetiapine, 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 (3)quetiapine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and risperidone both increase sedation. Use Caution/Monitor.
  
  quetiapine, risperidone. 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.

• ritonavir

  Monitor Closely (2)ritonavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, ritonavir. 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.

• rocuronium

  Monitor Closely (3)rocuronium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  rocuronium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• romidepsin

  Monitor Closely (1)quetiapine, romidepsin. 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.

• ropinirole

  Serious - Use Alternative (1)quetiapine decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

• rosiglitazone

  Monitor Closely (1)quetiapine, 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 (1)rucaparib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

• rufinamide

  Monitor Closely (1)rufinamide will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• safinamide

  Serious - Use Alternative (1)quetiapine 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)quetiapine and sage both increase sedation. Minor/Significance Unknown.

• salmeterol

  Monitor Closely (1)quetiapine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• saquinavir

  Monitor Closely (2)saquinavir increases levels of quetiapine by QTc interval. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Increased risk of QT prolongation and cardiac arrhythmias.
  
  quetiapine, saquinavir. 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.Serious - Use Alternative (1)saquinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• scopolamine

  Monitor Closely (3)scopolamine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  scopolamine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of scopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• scullcap

  Monitor Closely (1)quetiapine and scullcap both increase sedation. Use Caution/Monitor.

• secobarbital

  Monitor Closely (2)secobarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  secobarbital and quetiapine both increase sedation. Use Caution/Monitor.

• selegiline

  Monitor Closely (1)selegiline, quetiapine. 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).

• selinexor

  Serious - Use Alternative (1)selinexor, quetiapine. 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 (1)selpercatinib increases toxicity of quetiapine by QTc interval. Use Caution/Monitor.

• sevoflurane

  Serious - Use Alternative (1)sevoflurane and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• shepherd's purse

  Monitor Closely (1)quetiapine and shepherd's purse both increase sedation. Use Caution/Monitor.

• sitagliptin

  Monitor Closely (1)quetiapine, 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.

• sodium oxybate

  Serious - Use Alternative (1)quetiapine, 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 toxicity of quetiapine by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases effects of quetiapine 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

  Monitor Closely (2)sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of quetiapine by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases effects of quetiapine 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.

• solifenacin

  Monitor Closely (3)solifenacin decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  solifenacin decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• sorafenib

  Monitor Closely (1)sorafenib and quetiapine both increase QTc interval. Use Caution/Monitor.

• sotalol

  Monitor Closely (1)quetiapine, sotalol. 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.

• St John's Wort

  Serious - Use Alternative (1)St John's Wort will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• stiripentol

  Monitor Closely (2)stiripentol, quetiapine. 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, quetiapine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

• sufentanil

  Monitor Closely (1)sufentanil and quetiapine both increase sedation. Use Caution/Monitor.

• sufentanil SL

  Serious - Use Alternative (1)sufentanil SL, quetiapine. 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.

• sumatriptan

  Monitor Closely (1)sumatriptan, quetiapine. 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

  Monitor Closely (1)sumatriptan intranasal, quetiapine. 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).

• sunitinib

  Monitor Closely (1)quetiapine, sunitinib. 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.

• tacrolimus

  Monitor Closely (1)quetiapine, tacrolimus. 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.

• tapentadol

  Monitor Closely (1)tapentadol and quetiapine both increase sedation. Use Caution/Monitor.

• tazemetostat

  Monitor Closely (1)tazemetostat will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tecovirimat

  Monitor Closely (1)tecovirimat will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• telavancin

  Monitor Closely (1)quetiapine, telavancin. 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.

• temazepam

  Monitor Closely (1)temazepam and quetiapine both increase sedation. Use Caution/Monitor.

• terbutaline

  Monitor Closely (1)quetiapine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• tetrabenazine

  Monitor Closely (1)quetiapine and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.

• thioridazine

  Monitor Closely (3)quetiapine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and thioridazine both increase sedation. Use Caution/Monitor.
  
  quetiapine, thioridazine. 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.

• thiothixene

  Monitor Closely (3)quetiapine and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and thiothixene both increase sedation. Use Caution/Monitor.
  
  quetiapine, thiothixene. 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.

• tiotropium

  Monitor Closely (3)tiotropium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tiotropium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• tipranavir

  Monitor Closely (1)tipranavir will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration may increase quetiapine systemic exposure; more frequent monitoring of the clinical response to quetiapine as well as potential adverse events is recommended

• tolazamide

  Monitor Closely (1)quetiapine, 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 (1)quetiapine, 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.

• tolterodine

  Monitor Closely (3)tolterodine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tolterodine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• topiramate

  Monitor Closely (2)topiramate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• toremifene

  Monitor Closely (1)quetiapine, toremifene. 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.

• tramadol

  Monitor Closely (1)tramadol and quetiapine both increase sedation. Use Caution/Monitor.

• tranylcypromine

  Monitor Closely (1)tranylcypromine, quetiapine. 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 (1)quetiapine and trazodone both increase sedation. Use Caution/Monitor.

• triazolam

  Monitor Closely (1)triazolam and quetiapine both increase sedation. Use Caution/Monitor.

• triclabendazole

  Monitor Closely (1)triclabendazole and quetiapine both increase QTc interval. Use Caution/Monitor.

• triclofos

  Monitor Closely (1)triclofos and quetiapine both increase sedation. Use Caution/Monitor.

• trifluoperazine

  Monitor Closely (2)quetiapine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and trifluoperazine both increase sedation. Use Caution/Monitor.

• trihexyphenidyl

  Monitor Closely (1)quetiapine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

• trimipramine

  Monitor Closely (2)quetiapine and trimipramine both increase sedation. Use Caution/Monitor.
  
  quetiapine, trimipramine. 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.

• triprolidine

  Monitor Closely (1)triprolidine and quetiapine both increase sedation. Use Caution/Monitor.

• triptorelin

  Serious - Use Alternative (1)triptorelin increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.

• trospium chloride

  Monitor Closely (3)trospium chloride decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  trospium chloride decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• tucatinib

  Serious - Use Alternative (1)tucatinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

• umeclidinium bromide/vilanterol inhaled

  Serious - Use Alternative (1)quetiapine 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

  Monitor Closely (1)quetiapine, vandetanib. 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.

• vardenafil

  Monitor Closely (1)quetiapine, vardenafil. 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.

• vecuronium

  Monitor Closely (3)vecuronium decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  vecuronium decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  quetiapine increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• vemurafenib

  Serious - Use Alternative (1)vemurafenib and quetiapine 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 (1)venlafaxine, quetiapine. 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

  Monitor Closely (1)verapamil will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vilanterol/fluticasone furoate inhaled

  Serious - Use Alternative (1)quetiapine 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, quetiapine. 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

  Monitor Closely (1)voclosporin, quetiapine. Either increases effects of the other by QTc interval. Use Caution/Monitor.

• voriconazole

  Monitor Closely (2)voriconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  quetiapine, voriconazole. 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.

• vorinostat

  Monitor Closely (1)quetiapine, vorinostat. 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.

• voxelotor

  Serious - Use Alternative (1)voxelotor will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

• xylometazoline

  Monitor Closely (1)quetiapine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• yohimbine

  Monitor Closely (1)quetiapine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• zafirlukast

  Monitor Closely (1)zafirlukast will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ziconotide

  Monitor Closely (1)quetiapine and ziconotide both increase sedation. Use Caution/Monitor.

• ziprasidone

  Monitor Closely (3)quetiapine and ziprasidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and ziprasidone both increase sedation. Use Caution/Monitor.
  
  quetiapine, ziprasidone. 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.

• zolmitriptan

  Monitor Closely (1)zolmitriptan, quetiapine. 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).

• zotepine

  Monitor Closely (2)quetiapine and zotepine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  quetiapine and zotepine both increase sedation. Use Caution/Monitor.