fluphenazine (Rx)

Psychotic Disorders

Fluphenazine hydrochloride

• 2.5-10 mg/day PO divided q6-8hr initially; maintenance: 1-5 mg PO/IM divided q6-8hr; not to exceed 40 mg/day

Fluphenazine decanoate

• 16.25-25 mg (25 mg/mL) IM/SC q2weeks; after achieving steady state, effects of a single injection may last 4-6 weeks; use caution titrating dosages; if doses >50 mg needed; use increments of 12.5 mg; not to exceed 100 mg

Dosing considerations

• Conversion from oral hydrochloride salt to decanoate dosage form: 12.5 mg of decanoate every 3 weeks is approximately equivalent to 10 mg/day of oral hydrochloride and 12.5 mg/day IM/SC

Dosing Modifications

Renal impairment: Use with caution; monitor

Hepatic impairment: Use with caution; monitor

Safety and efficacy not established

1-2.5 mg/day PO; dosage titrated according to response

Contraindicated (11)

• amisulpride

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

• disopyramide

  fluphenazine and disopyramide both increase QTc interval. Contraindicated.

• fezolinetant

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

• ibutilide

  fluphenazine and ibutilide both increase QTc interval. Contraindicated.

• indapamide

  fluphenazine and indapamide both increase QTc interval. Contraindicated.

• metrizamide

  fluphenazine, metrizamide. Mechanism: unknown. Contraindicated. Risk of seizure. D/C phenothiazine 24h before admin. of metrizamide.

• pentamidine

  fluphenazine and pentamidine both increase QTc interval. Contraindicated.

• pimozide

  fluphenazine and pimozide both increase QTc interval. Contraindicated.

• procainamide

  fluphenazine and procainamide both increase QTc interval. Contraindicated.

• quinidine

  fluphenazine and quinidine both increase QTc interval. Contraindicated.

• sotalol

  fluphenazine and sotalol both increase QTc interval. Contraindicated.

Serious - Use Alternative (94)

• adagrasib

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

• aminolevulinic acid oral

  aminolevulinic acid oral, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.

• aminolevulinic acid topical

  fluphenazine increases toxicity of aminolevulinic acid topical by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of photosensitizing drugs may enhance the phototoxic reaction to photodynamic therapy with aminolevulinic acid.

• amiodarone

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

• amitriptyline

  fluphenazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.

• amoxapine

  fluphenazine and amoxapine both increase QTc interval. Avoid or Use Alternate Drug.

• apomorphine

  fluphenazine decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.
  
  apomorphine and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• aripiprazole

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

• arsenic trioxide

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

• artemether/lumefantrine

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

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen, fluphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).

• bromocriptine

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

• cabergoline

  fluphenazine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

• calcium/magnesium/potassium/sodium oxybates

  fluphenazine, 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.

• chlorpromazine

  chlorpromazine and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• clarithromycin

  fluphenazine and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.

• clomipramine

  fluphenazine and clomipramine both increase QTc interval. Avoid or Use Alternate Drug.

• dacomitinib

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

• degarelix

  degarelix and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• desipramine

  fluphenazine and desipramine both increase QTc interval. Avoid or Use Alternate Drug.

• dofetilide

  fluphenazine and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.

• dopamine

  fluphenazine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

• dosulepin

  fluphenazine and dosulepin both increase QTc interval. Avoid or Use Alternate Drug.

• doxepin

  fluphenazine and doxepin both increase QTc interval. Avoid or Use Alternate Drug.

• dronedarone

  fluphenazine and dronedarone both increase QTc interval. Avoid or Use Alternate Drug.

• droperidol

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

• epinephrine

  epinephrine and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• epinephrine racemic

  epinephrine racemic and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin base

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

• erythromycin ethylsuccinate

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

• erythromycin lactobionate

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

• erythromycin stearate

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

• fentanyl

  fentanyl, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl intranasal

  fentanyl intranasal, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transdermal

  fentanyl transdermal, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transmucosal

  fentanyl transmucosal, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fexinidazole

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

• fluconazole

  fluphenazine and fluconazole both increase QTc interval. Avoid or Use Alternate Drug.

• fluoxetine

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

• formoterol

  fluphenazine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.

• givosiran

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

• haloperidol

  fluphenazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

• hydrocodone

  hydrocodone, fluphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).

• hydroxychloroquine sulfate

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

• imipramine

  fluphenazine and imipramine both increase QTc interval. Avoid or Use Alternate Drug.

• ivosidenib

  ivosidenib and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.

• ketoconazole

  fluphenazine and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.

• lefamulin

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

• levodopa

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

• levodopa inhaled

  fluphenazine decreases effects of levodopa inhaled by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Phenothiazine/1st generation antipsychotics inhibit dopamine D2 receptors in varying degrees.

• levoketoconazole

  fluphenazine and levoketoconazole both increase QTc interval. Avoid or Use Alternate Drug.

• lisuride

  fluphenazine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

• lofepramine

  fluphenazine and lofepramine both increase QTc interval. Avoid or Use Alternate Drug.

• lumefantrine

  fluphenazine and lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

• macimorelin

  macimorelin and fluphenazine 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

  fluphenazine and maprotiline both increase QTc interval. Avoid or Use Alternate Drug.

• methyl aminolevulinate

  fluphenazine, methyl aminolevulinate. Either increases levels of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.

• methyldopa

  fluphenazine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

• metoclopramide intranasal

  fluphenazine, 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.
  
  fluphenazine 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.

• mirtazapine

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

• mobocertinib

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

• moxifloxacin

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

• nilotinib

  fluphenazine and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.

• nortriptyline

  fluphenazine and nortriptyline both increase QTc interval. Avoid or Use Alternate Drug.

• octreotide

  fluphenazine and octreotide both increase QTc interval. Avoid or Use Alternate Drug.

• octreotide (Antidote)

  fluphenazine and octreotide (Antidote) both increase QTc interval. Avoid or Use Alternate Drug.

• olopatadine intranasal

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

• ondansetron

  fluphenazine 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.

• paroxetine

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

• perphenazine

  fluphenazine and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• pramipexole

  fluphenazine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

• prochlorperazine

  fluphenazine and prochlorperazine both increase QTc interval. Avoid or Use Alternate Drug.

• promazine

  fluphenazine and promazine both increase QTc interval. Avoid or Use Alternate Drug.

• promethazine

  fluphenazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

• protriptyline

  fluphenazine and protriptyline both increase QTc interval. Avoid or Use Alternate Drug.

• quinidine

  quinidine, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.

• ropinirole

  fluphenazine decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

• safinamide

  fluphenazine 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 increases levels of fluphenazine by QTc interval. Avoid or Use Alternate Drug. Potential for increased toxicity. .

• selinexor

  selinexor, fluphenazine. 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.

• sodium oxybate

  fluphenazine, 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.

• sufentanil SL

  sufentanil SL, fluphenazine. 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.

• tetrabenazine

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

• thioridazine

  fluphenazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.

• trazodone

  fluphenazine and trazodone both increase QTc interval. Avoid or Use Alternate Drug.

• tretinoin

  fluphenazine, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• tretinoin topical

  fluphenazine, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• trifluoperazine

  fluphenazine and trifluoperazine both increase QTc interval. Avoid or Use Alternate Drug.

• trimipramine

  fluphenazine and trimipramine both increase QTc interval. Avoid or Use Alternate Drug.

• umeclidinium bromide/vilanterol inhaled

  fluphenazine 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.

• venlafaxine

  fluphenazine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.

• vilanterol/fluticasone furoate inhaled

  fluphenazine 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.

• yohimbe

  yohimbe decreases effects of fluphenazine by pharmacodynamic antagonism. Contraindicated.

• ziprasidone

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

Monitor Closely (354)

• abiraterone

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

• abobotulinumtoxinA

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

• aclidinium

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

• acrivastine

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

• albiglutide

  fluphenazine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.

• albuterol

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

• alfentanil

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

• alfuzosin

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

• almotriptan

  almotriptan, fluphenazine. 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 fluphenazine both increase sedation. Use Caution/Monitor.

• amifampridine

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

• amisulpride

  fluphenazine and amisulpride both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended if coadministered.

• amitriptyline

  fluphenazine and amitriptyline both increase sedation. Use Caution/Monitor.

• amobarbital

  amobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• amoxapine

  fluphenazine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.
  
  fluphenazine and amoxapine both increase sedation. Use Caution/Monitor.

• anagrelide

  anagrelide and fluphenazine both increase QTc interval. Use Caution/Monitor.

• anticholinergic/sedative combos

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

• apomorphine

  fluphenazine and apomorphine both increase sedation. Use Caution/Monitor.

• arformoterol

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

• aripiprazole

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

• armodafinil

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

• artemether

  artemether and fluphenazine both increase QTc interval. Use Caution/Monitor.

• artemether/lumefantrine

  artemether/lumefantrine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• asenapine

  asenapine and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  asenapine and fluphenazine both increase sedation. Use Caution/Monitor.

• asenapine transdermal

  asenapine transdermal and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  asenapine transdermal and fluphenazine both increase sedation. Use Caution/Monitor.

• atomoxetine

  atomoxetine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• atracurium

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

• atropine

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

• atropine IV/IM

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

• avapritinib

  avapritinib and fluphenazine both increase sedation. Use Caution/Monitor.

• azelastine

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

• azithromycin

  fluphenazine and azithromycin both increase QTc interval. Use Caution/Monitor.

• baclofen

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

• bedaquiline

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

• belladonna alkaloids

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

• belladonna and opium

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

• benperidol

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

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen and fluphenazine both increase sedation. Use Caution/Monitor.

• benzphetamine

  fluphenazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, benzphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• benztropine

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

• brexanolone

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

• brexpiprazole

  brexpiprazole and fluphenazine both increase sedation. Use Caution/Monitor.

• brimonidine

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

• brivaracetam

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

• brompheniramine

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

• buprenorphine

  buprenorphine and fluphenazine both increase sedation. Use Caution/Monitor.
  
  buprenorphine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• buprenorphine buccal

  buprenorphine buccal and fluphenazine both increase sedation. Use Caution/Monitor.
  
  buprenorphine buccal and fluphenazine both increase QTc interval. Use Caution/Monitor.

• buprenorphine subdermal implant

  buprenorphine subdermal implant and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  buprenorphine subdermal implant and fluphenazine both increase sedation. Use Caution/Monitor.

• buprenorphine transdermal

  buprenorphine transdermal and fluphenazine both increase QTc interval. Use Caution/Monitor.

• buprenorphine, long-acting injection

  fluphenazine 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.
  
  buprenorphine, long-acting injection and fluphenazine both increase QTc interval. Use Caution/Monitor.

• bupropion

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

• butabarbital

  butabarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• butalbital

  butalbital and fluphenazine both increase sedation. Use Caution/Monitor.

• butorphanol

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

• caffeine

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

• carbinoxamine

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

• carisoprodol

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

• ceritinib

  ceritinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• chloral hydrate

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

• chlordiazepoxide

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

• chlorpheniramine

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

• chlorpromazine

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

• chlorzoxazone

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

• cigarette smoking

  cigarette smoking decreases levels of fluphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

• cinnarizine

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

• cisatracurium

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

• citalopram

  citalopram and fluphenazine both increase QTc interval. Use Caution/Monitor.

• clemastine

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

• clobazam

  clobazam will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.
  
  fluphenazine, 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

  fluphenazine and clomipramine both increase sedation. Use Caution/Monitor.

• clonazepam

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

• clonidine

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

• clorazepate

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

• clozapine

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

• codeine

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

• crizotinib

  crizotinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• cyclizine

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

• cyclobenzaprine

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

• cyproheptadine

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

• dantrolene

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

• daridorexant

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

• darifenacin

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

• dasatinib

  fluphenazine and dasatinib both increase QTc interval. Modify Therapy/Monitor Closely.

• desflurane

  desflurane and fluphenazine both increase sedation. Use Caution/Monitor.
  
  desflurane and fluphenazine both increase QTc interval. Use Caution/Monitor.

• desipramine

  fluphenazine and desipramine both increase sedation. Use Caution/Monitor.

• desvenlafaxine

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

• deutetrabenazine

  fluphenazine 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.
  
  fluphenazine and deutetrabenazine both increase sedation. Use Caution/Monitor.
  
  deutetrabenazine and fluphenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).

• dexchlorpheniramine

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

• dexfenfluramine

  fluphenazine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, dexfenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• dexmedetomidine

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

• dexmethylphenidate

  fluphenazine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, dexmethylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• dextroamphetamine

  fluphenazine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, dextroamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• dextromethorphan

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

• diamorphine

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

• diazepam

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

• dicyclomine

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

• diethylpropion

  fluphenazine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, diethylpropion. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• difelikefalin

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

• difenoxin hcl

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

• dihydroergotamine

  dihydroergotamine, fluphenazine. 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).

• dimenhydrinate

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

• diphenhydramine

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

• diphenoxylate hcl

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

• dipipanone

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

• dobutamine

  fluphenazine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, dobutamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• dofetilide

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

• dolasetron

  fluphenazine and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.

• donepezil

  donepezil and fluphenazine both increase QTc interval. Use Caution/Monitor.

• donepezil transdermal

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

• dopamine

  fluphenazine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, dopamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• dopexamine

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

• dosulepin

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

• doxepin

  fluphenazine and doxepin both increase sedation. Use Caution/Monitor.

• doxylamine

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

• droperidol

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

• efavirenz

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

• eletriptan

  eletriptan, fluphenazine. 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).

• eliglustat

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

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

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

• encorafenib

  encorafenib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• entrectinib

  entrectinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• ephedrine

  fluphenazine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, ephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• epinephrine

  fluphenazine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, epinephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.

• epinephrine racemic

  fluphenazine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.

• ergoloid mesylates

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

• eribulin

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

• escitalopram

  escitalopram increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.

• esketamine intranasal

  esketamine intranasal, fluphenazine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• estazolam

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

• ethanol

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

• etomidate

  etomidate and fluphenazine both increase sedation. Use Caution/Monitor.

• fedratinib

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

• fenfluramine

  fluphenazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• fentanyl

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

• fingolimod

  fingolimod and fluphenazine both increase QTc interval. Use Caution/Monitor.

• flavoxate

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

• flecainide

  fluphenazine and flecainide both increase QTc interval. Modify Therapy/Monitor Closely.

• flibanserin

  flibanserin, fluphenazine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. 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).

• flurazepam

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

• fluvoxamine

  fluvoxamine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• formoterol

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

• foscarnet

  fluphenazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

• fostemsavir

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

• frovatriptan

  frovatriptan, fluphenazine. 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).

• ganaxolone

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

• gemifloxacin

  gemifloxacin and fluphenazine both increase QTc interval. Use Caution/Monitor.

• gilteritinib

  gilteritinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• glycopyrrolate

  fluphenazine increases toxicity of glycopyrrolate by unknown mechanism. Use Caution/Monitor.
  
  fluphenazine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• glycopyrrolate inhaled

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

• glycopyrronium tosylate topical

  glycopyrronium tosylate topical, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.

• granisetron

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

• guanfacine

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

• haloperidol

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

• henbane

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

• homatropine

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

• hydromorphone

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

• hydroxyzine

  hydroxyzine and fluphenazine both increase sedation. Use Caution/Monitor.
  
  hydroxyzine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• hyoscyamine

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

• hyoscyamine spray

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

• iloperidone

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

• imipramine

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

• incobotulinumtoxinA

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

• insulin degludec

  fluphenazine decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.

• insulin degludec/insulin aspart

  fluphenazine decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.

• insulin inhaled

  fluphenazine decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.

• ipratropium

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

• isoflurane

  isoflurane and fluphenazine both increase QTc interval. Use Caution/Monitor.

• isoproterenol

  fluphenazine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, isoproterenol. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• itraconazole

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

• ketotifen, ophthalmic

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

• lapatinib

  fluphenazine and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.

• lasmiditan

  lasmiditan, fluphenazine. 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, fluphenazine. 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.

• levalbuterol

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

• levofloxacin

  fluphenazine and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

• levomilnacipran

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

• linezolid

  linezolid, fluphenazine. 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

  fluphenazine, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.

• lisdexamfetamine

  fluphenazine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, lisdexamfetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• lithium

  lithium, fluphenazine. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved.
  
  lithium, fluphenazine. 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).
  
  lithium and fluphenazine both increase QTc interval. Use Caution/Monitor.

• lofepramine

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

• lofexidine

  fluphenazine and lofexidine both increase sedation. Use Caution/Monitor.

• loprazolam

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

• lorazepam

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

• lorcaserin

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

• lormetazepam

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

• loxapine

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

• loxapine inhaled

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

• lumefantrine

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

• lurasidone

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

• maprotiline

  fluphenazine and maprotiline both increase sedation. Use Caution/Monitor.

• marijuana

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

• meclizine

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

• melatonin

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

• meperidine

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

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

• metaproterenol

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

• metaxalone

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

• metformin

  fluphenazine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.

• methadone

  fluphenazine and methadone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  methadone and fluphenazine both increase sedation. Use Caution/Monitor.
  
  methadone, fluphenazine. 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

  fluphenazine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, methamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• methocarbamol

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

• methoxsalen

  methoxsalen, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

• methscopolamine

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

• methylenedioxymethamphetamine

  fluphenazine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, methylenedioxymethamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• methylergonovine

  methylergonovine, fluphenazine. 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

  fluphenazine, methylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.

• metoclopramide

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

• midazolam

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

• midazolam intranasal

  midazolam intranasal, fluphenazine. 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

  fluphenazine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, midodrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• mifepristone

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

• milnacipran

  milnacipran, fluphenazine. 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).

• mirabegron

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

• mirtazapine

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

• modafinil

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

• morphine

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

• motherwort

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

• moxonidine

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

• nabilone

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

• nalbuphine

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

• naratriptan

  naratriptan, fluphenazine. 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).

• norepinephrine

  fluphenazine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, norepinephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• nortriptyline

  fluphenazine and nortriptyline both increase sedation. Use Caution/Monitor.

• ofloxacin

  fluphenazine and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

• olanzapine

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

• oliceridine

  oliceridine, fluphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).

• olodaterol inhaled

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

• opium tincture

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

• orphenadrine

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

• osilodrostat

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

• osimertinib

  osimertinib and fluphenazine 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 and fluphenazine both increase QTc interval. Use Caution/Monitor.

• oxazepam

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

• oxybutynin

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

• oxybutynin topical

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

• oxybutynin transdermal

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

• oxycodone

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

• oxymorphone

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

• ozanimod

  ozanimod and fluphenazine 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

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

• pancuronium

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

• papaveretum

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

• papaverine

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

• paroxetine

  paroxetine, fluphenazine. 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

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

• pazopanib

  fluphenazine and pazopanib both increase QTc interval. Use Caution/Monitor.

• pentazocine

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

• pentobarbital

  pentobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• perphenazine

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

• phendimetrazine

  fluphenazine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, phendimetrazine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• phenelzine

  phenelzine, fluphenazine. 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 and fluphenazine both increase sedation. Use Caution/Monitor.

• phentermine

  fluphenazine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, phentermine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• phenylephrine

  fluphenazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• phenylephrine PO

  fluphenazine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  fluphenazine, phenylephrine PO. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• pholcodine

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

• pimozide

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

• pirbuterol

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

• porfimer

  fluphenazine, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

• posaconazole

  fluphenazine and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• pralidoxime

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

• primaquine

  primaquine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• primidone

  primidone and fluphenazine both increase sedation. Use Caution/Monitor.

• procarbazine

  procarbazine, fluphenazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Excessive sedation.
  
  procarbazine, fluphenazine. 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

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

• promethazine

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

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

• propantheline

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

• propofol

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

• propylhexedrine

  fluphenazine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, propylhexedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• protriptyline

  fluphenazine and protriptyline both increase sedation. Use Caution/Monitor.

• pseudoephedrine

  fluphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• quazepam

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

• quetiapine

  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.

• quinidine

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

• quinine

  fluphenazine and quinine both increase QTc interval. Use Caution/Monitor.

• ramelteon

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

• ranolazine

  fluphenazine and ranolazine both increase QTc interval. Modify Therapy/Monitor Closely.

• rapacuronium

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

• remimazolam

  remimazolam, fluphenazine. 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.

• ribociclib

  ribociclib increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.

• rimabotulinumtoxinB

  fluphenazine increases effects of rimabotulinumtoxinB by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• risperidone

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

• rizatriptan

  rizatriptan, fluphenazine. 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).

• rocuronium

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

• rolapitant

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

• romidepsin

  fluphenazine and romidepsin both increase QTc interval. Modify Therapy/Monitor Closely.

• salmeterol

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

• scopolamine

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

• scullcap

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

• secobarbital

  secobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• selegiline

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

• serdexmethylphenidate/dexmethylphenidate

  fluphenazine, serdexmethylphenidate/dexmethylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• sevoflurane

  sevoflurane and fluphenazine both increase sedation. Use Caution/Monitor.
  
  sevoflurane and fluphenazine both increase QTc interval. Use Caution/Monitor.

• shepherd's purse

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

• siponimod

  siponimod and fluphenazine both increase QTc interval. Use Caution/Monitor.

• smoking

  smoking decreases levels of fluphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

• sodium sulfate/?magnesium sulfate/potassium chloride

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

• sodium sulfate/potassium sulfate/magnesium sulfate

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

• sorafenib

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

• stiripentol

  stiripentol, fluphenazine. 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 fluphenazine both increase sedation. Use Caution/Monitor.

• sulfamethoxazole

  fluphenazine and sulfamethoxazole both increase QTc interval. Modify Therapy/Monitor Closely.

• sumatriptan

  sumatriptan, fluphenazine. 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, fluphenazine. 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

  sunitinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• tacrolimus

  tacrolimus and fluphenazine both increase QTc interval. Use Caution/Monitor.

• tapentadol

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

• teduglutide

  teduglutide increases levels of fluphenazine by Other (see comment). Use Caution/Monitor. Comment: Teduglutide may increase absorption of concomitant PO medications; caution with with drugs requiring titration or those with a narrow therapeutic index; dose adjustment may be necessary.

• telavancin

  fluphenazine and telavancin both increase QTc interval. Modify Therapy/Monitor Closely.

• temazepam

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

• terbinafine

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

• terbutaline

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

• tetrabenazine

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

• thioridazine

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

• thiothixene

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

• tiotropium

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

• tobacco use

  tobacco use decreases levels of fluphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

• tolterodine

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

• topiramate

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

• tramadol

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

• tranylcypromine

  tranylcypromine, fluphenazine. 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

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

• triazolam

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

• triclofos

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

• trifluoperazine

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

• trihexyphenidyl

  trihexyphenidyl decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

• trimethoprim

  fluphenazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

• trimipramine

  fluphenazine and trimipramine both increase sedation. Use Caution/Monitor.

• triprolidine

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

• tropisetron

  fluphenazine and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely.

• trospium chloride

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

• valbenazine

  valbenazine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• vecuronium

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

• venlafaxine

  venlafaxine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  venlafaxine, fluphenazine. 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).

• vilazodone

  vilazodone, fluphenazine. 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).

• voriconazole

  fluphenazine and voriconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• vorinostat

  vorinostat and fluphenazine both increase QTc interval. Use Caution/Monitor.

• xylometazoline

  fluphenazine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, xylometazoline. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• yohimbine

  fluphenazine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fluphenazine, yohimbine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• ziconotide

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

• ziprasidone

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

• zolmitriptan

  zolmitriptan, fluphenazine. 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).

• zolpidem

  fluphenazine will increase the level or effect of zolpidem by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Additive effect of decreased alertness and psychomotor performance

• zotepine

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

Minor (59)

• amiodarone

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

• amitriptyline

  amitriptyline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  amitriptyline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• amoxapine

  amoxapine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  amoxapine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  fluphenazine, amoxapine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• asenapine

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

• atropine

  fluphenazine increases toxicity of atropine by unknown mechanism. Minor/Significance Unknown.

• atropine IV/IM

  fluphenazine increases toxicity of atropine IV/IM by unknown mechanism. Minor/Significance Unknown.

• benazepril

  fluphenazine increases effects of benazepril by unspecified interaction mechanism. Minor/Significance Unknown. Enhanced hypotensive effects.

• brimonidine

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

• bupropion

  fluphenazine increases toxicity of bupropion by unspecified interaction mechanism. Minor/Significance Unknown. May lower seizure threshold; keep bupropion dose as low as possible.

• captopril

  fluphenazine increases effects of captopril by unspecified interaction mechanism. Minor/Significance Unknown. Both drugs lower blood pressure. Monitor blood pressure.

• celecoxib

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

• chasteberry

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

• chloroquine

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

• cimetidine

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

• clomipramine

  clomipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  clomipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• darifenacin

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

• desipramine

  desipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  desipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• diphenhydramine

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

• doxepin

  doxepin, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  doxepin, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• dronedarone

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

• duloxetine

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

• enalapril

  fluphenazine increases effects of enalapril by unspecified interaction mechanism. Minor/Significance Unknown.

• ethanol

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

• eucalyptus

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

• fosinopril

  fluphenazine increases effects of fosinopril by unspecified interaction mechanism. Minor/Significance Unknown.

• haloperidol

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

• imatinib

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

• imidapril

  fluphenazine increases effects of imidapril by unspecified interaction mechanism. Minor/Significance Unknown.

• imipramine

  imipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  imipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• lisinopril

  fluphenazine increases effects of lisinopril by unspecified interaction mechanism. Minor/Significance Unknown.

• lofepramine

  lofepramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  lofepramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• maprotiline

  maprotiline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  maprotiline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• maraviroc

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

• marijuana

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

• metyrapone

  fluphenazine decreases effects of metyrapone by unspecified interaction mechanism. Minor/Significance Unknown.

• metyrosine

  metyrosine increases toxicity of fluphenazine by pharmacodynamic synergism. Minor/Significance Unknown. Increased extrapyramidal symptoms.

• moexipril

  fluphenazine increases effects of moexipril by unspecified interaction mechanism. Minor/Significance Unknown.

• nilotinib

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

• nortriptyline

  nortriptyline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  nortriptyline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• oxybutynin

  oxybutynin increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.

• oxybutynin topical

  oxybutynin topical increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.

• oxybutynin transdermal

  oxybutynin transdermal increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.

• parecoxib

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

• perindopril

  fluphenazine increases effects of perindopril by unspecified interaction mechanism. Minor/Significance Unknown.

• perphenazine

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

• protriptyline

  protriptyline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  protriptyline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• pyrimethamine

  pyrimethamine increases levels of fluphenazine by decreasing metabolism. Minor/Significance Unknown.

• quinacrine

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

• quinapril

  fluphenazine increases effects of quinapril by unspecified interaction mechanism. Minor/Significance Unknown.

• ramipril

  fluphenazine increases effects of ramipril by unspecified interaction mechanism. Minor/Significance Unknown.

• ranolazine

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

• ritonavir

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

• sage

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

• sertraline

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

• thioridazine

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

• tipranavir

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

• trandolapril

  fluphenazine increases effects of trandolapril by unspecified interaction mechanism. Minor/Significance Unknown.

• trazodone

  trazodone, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.
  
  trazodone, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

• trimipramine

  trimipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  trimipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• abiraterone

  Monitor Closely (1)abiraterone increases levels of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

• abobotulinumtoxinA

  Monitor Closely (1)abobotulinumtoxinA increases effects of fluphenazine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

• aclidinium

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

• acrivastine

  Monitor Closely (1)acrivastine and fluphenazine both increase sedation. Use Caution/Monitor.

• adagrasib

  Serious - Use Alternative (1)adagrasib, fluphenazine. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.

• albiglutide

  Monitor Closely (1)fluphenazine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.

• albuterol

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

• alfentanil

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

• alfuzosin

  Monitor Closely (2)fluphenazine and alfuzosin both increase QTc interval. Use Caution/Monitor.
  
  alfuzosin and fluphenazine both increase QTc interval. Use Caution/Monitor.

• almotriptan

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

• amifampridine

  Monitor Closely (1)fluphenazine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• aminolevulinic acid oral

  Serious - Use Alternative (1)aminolevulinic acid oral, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.

• aminolevulinic acid topical

  Serious - Use Alternative (1)fluphenazine increases toxicity of aminolevulinic acid topical by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of photosensitizing drugs may enhance the phototoxic reaction to photodynamic therapy with aminolevulinic acid.

• amiodarone

  Serious - Use Alternative (1)fluphenazine and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)amiodarone will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• amisulpride

  Contraindicated (1)amisulpride, fluphenazine. Either increases toxicity of the other by Other (see comment). Contraindicated. Comment: Increases risk of neuroleptic malignant syndrome.Monitor Closely (1)fluphenazine and amisulpride both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended if coadministered.

• amitriptyline

  Monitor Closely (1)fluphenazine and amitriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)amitriptyline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  amitriptyline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• amobarbital

  Monitor Closely (1)amobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• amoxapine

  Monitor Closely (2)fluphenazine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.
  
  fluphenazine and amoxapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and amoxapine both increase QTc interval. Avoid or Use Alternate Drug.Minor (3)amoxapine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  amoxapine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  fluphenazine, amoxapine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• anagrelide

  Monitor Closely (1)anagrelide and fluphenazine both increase QTc interval. Use Caution/Monitor.

• anticholinergic/sedative combos

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

• apomorphine

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

• arformoterol

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

• aripiprazole

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

• armodafinil

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

• arsenic trioxide

  Serious - Use Alternative (1)fluphenazine and arsenic trioxide both increase QTc interval. Avoid or Use Alternate Drug.

• artemether

  Monitor Closely (1)artemether and fluphenazine both increase QTc interval. Use Caution/Monitor.

• artemether/lumefantrine

  Monitor Closely (1)artemether/lumefantrine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine

  Monitor Closely (2)asenapine and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  asenapine and fluphenazine both increase sedation. Use Caution/Monitor.Minor (1)asenapine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• asenapine transdermal

  Monitor Closely (2)asenapine transdermal and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  asenapine transdermal and fluphenazine both increase sedation. Use Caution/Monitor.

• atomoxetine

  Monitor Closely (1)atomoxetine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• atracurium

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

• atropine

  Monitor Closely (3)atropine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)fluphenazine increases toxicity of atropine by unknown mechanism. Minor/Significance Unknown.

• atropine IV/IM

  Monitor Closely (3)fluphenazine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  atropine IV/IM decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atropine IV/IM decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.Minor (1)fluphenazine increases toxicity of atropine IV/IM by unknown mechanism. Minor/Significance Unknown.

• avapritinib

  Monitor Closely (1)avapritinib and fluphenazine both increase sedation. Use Caution/Monitor.

• azelastine

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

• azithromycin

  Monitor Closely (1)fluphenazine and azithromycin both increase QTc interval. Use Caution/Monitor.

• baclofen

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

• bedaquiline

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

• benazepril

  Minor (1)fluphenazine increases effects of benazepril by unspecified interaction mechanism. Minor/Significance Unknown. Enhanced hypotensive effects.

• benperidol

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

• benzhydrocodone/acetaminophen

  Monitor Closely (1)benzhydrocodone/acetaminophen and fluphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)benzhydrocodone/acetaminophen, fluphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).

• benzphetamine

  Monitor Closely (2)fluphenazine, benzphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• benztropine

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

• brexanolone

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

• brexpiprazole

  Monitor Closely (1)brexpiprazole and fluphenazine both increase sedation. Use Caution/Monitor.

• brimonidine

  Monitor Closely (1)brimonidine and fluphenazine both increase sedation. Use Caution/Monitor.Minor (1)brimonidine increases effects of fluphenazine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

• brivaracetam

  Monitor Closely (1)brivaracetam and fluphenazine both increase sedation. Use Caution/Monitor.

• bromocriptine

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

• brompheniramine

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

• buprenorphine

  Monitor Closely (2)buprenorphine and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  buprenorphine and fluphenazine both increase sedation. Use Caution/Monitor.

• buprenorphine buccal

  Monitor Closely (2)buprenorphine buccal and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  buprenorphine buccal and fluphenazine both increase sedation. Use Caution/Monitor.

• buprenorphine subdermal implant

  Monitor Closely (2)buprenorphine subdermal implant and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  buprenorphine subdermal implant and fluphenazine both increase sedation. Use Caution/Monitor.

• buprenorphine transdermal

  Monitor Closely (1)buprenorphine transdermal and fluphenazine both increase QTc interval. Use Caution/Monitor.

• buprenorphine, long-acting injection

  Monitor Closely (2)buprenorphine, long-acting injection and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  fluphenazine 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.

• bupropion

  Monitor Closely (1)bupropion will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Minor (1)fluphenazine increases toxicity of bupropion by unspecified interaction mechanism. Minor/Significance Unknown. May lower seizure threshold; keep bupropion dose as low as possible.

• butabarbital

  Monitor Closely (1)butabarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• butalbital

  Monitor Closely (1)butalbital and fluphenazine both increase sedation. Use Caution/Monitor.

• butorphanol

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

• cabergoline

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

• caffeine

  Monitor Closely (1)fluphenazine 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)fluphenazine, 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

  Minor (1)fluphenazine increases effects of captopril by unspecified interaction mechanism. Minor/Significance Unknown. Both drugs lower blood pressure. Monitor blood pressure.

• carbinoxamine

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

• carisoprodol

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

• celecoxib

  Minor (1)celecoxib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• ceritinib

  Monitor Closely (1)ceritinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• chasteberry

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

• chloral hydrate

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

• chlordiazepoxide

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

• chloroquine

  Minor (3)chloroquine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
  
  chloroquine increases levels of fluphenazine by decreasing metabolism. Minor/Significance Unknown.
  
  chloroquine increases toxicity of fluphenazine by QTc interval. Minor/Significance Unknown.

• chlorpheniramine

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

• chlorpromazine

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

• chlorzoxazone

  Monitor Closely (1)chlorzoxazone and fluphenazine both increase sedation. Use Caution/Monitor.

• cigarette smoking

  Monitor Closely (1)cigarette smoking decreases levels of fluphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

• cimetidine

  Minor (1)cimetidine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• cinnarizine

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

• cisatracurium

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

• citalopram

  Monitor Closely (1)citalopram and fluphenazine both increase QTc interval. Use Caution/Monitor.

• clarithromycin

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

• clemastine

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

• clobazam

  Monitor Closely (2)clobazam will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.
  
  fluphenazine, 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 (1)fluphenazine and clomipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and clomipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)clomipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  clomipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• clonazepam

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

• clonidine

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

• clorazepate

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

• clozapine

  Monitor Closely (3)clozapine and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  clozapine and fluphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  clozapine and fluphenazine both increase sedation. Use Caution/Monitor.

• codeine

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

• crizotinib

  Monitor Closely (1)crizotinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• cyclizine

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

• cyclobenzaprine

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

• cyproheptadine

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

• dacomitinib

  Serious - Use Alternative (1)dacomitinib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.

• dantrolene

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

• daridorexant

  Monitor Closely (1)fluphenazine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• darifenacin

  Monitor Closely (3)darifenacin decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  darifenacin decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)darifenacin will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• dasatinib

  Monitor Closely (1)fluphenazine and dasatinib both increase QTc interval. Modify Therapy/Monitor Closely.

• degarelix

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

• desflurane

  Monitor Closely (2)desflurane and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  desflurane and fluphenazine both increase sedation. Use Caution/Monitor.

• desipramine

  Monitor Closely (1)fluphenazine and desipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and desipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)desipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  desipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• desvenlafaxine

  Monitor Closely (1)desvenlafaxine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg

• deutetrabenazine

  Monitor Closely (3)fluphenazine and deutetrabenazine both increase sedation. Use Caution/Monitor.
  
  deutetrabenazine and fluphenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).
  
  fluphenazine 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.

• dexchlorpheniramine

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

• dexfenfluramine

  Monitor Closely (2)fluphenazine, dexfenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dexmedetomidine

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

• dexmethylphenidate

  Monitor Closely (2)fluphenazine, dexmethylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextroamphetamine

  Monitor Closely (2)fluphenazine, dextroamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextromethorphan

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

• diamorphine

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

• diazepam

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

• dicyclomine

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

• diethylpropion

  Monitor Closely (2)fluphenazine, diethylpropion. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• difelikefalin

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

• difenoxin hcl

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

• dihydroergotamine

  Monitor Closely (1)dihydroergotamine, fluphenazine. 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).

• dimenhydrinate

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

• diphenhydramine

  Monitor Closely (4)diphenhydramine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  diphenhydramine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  diphenhydramine and fluphenazine both increase sedation. Use Caution/Monitor.Minor (1)diphenhydramine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• diphenoxylate hcl

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

• dipipanone

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

• disopyramide

  Contraindicated (1)fluphenazine and disopyramide both increase QTc interval. Contraindicated.

• dobutamine

  Monitor Closely (2)fluphenazine, dobutamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dofetilide

  Monitor Closely (1)dofetilide increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.

• dolasetron

  Monitor Closely (1)fluphenazine and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.

• donepezil

  Monitor Closely (1)donepezil and fluphenazine both increase QTc interval. Use Caution/Monitor.

• donepezil transdermal

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

• dopamine

  Monitor Closely (2)fluphenazine, dopamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

• dopexamine

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

• dosulepin

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

• doxepin

  Monitor Closely (1)fluphenazine and doxepin both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and doxepin both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)doxepin, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  doxepin, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• doxylamine

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

• dronedarone

  Serious - Use Alternative (1)fluphenazine and dronedarone both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)dronedarone will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• droperidol

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

• duloxetine

  Minor (1)duloxetine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• efavirenz

  Monitor Closely (1)efavirenz and fluphenazine both increase QTc interval. Use Caution/Monitor.

• eletriptan

  Monitor Closely (1)eletriptan, fluphenazine. 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).

• eliglustat

  Monitor Closely (2)eliglustat increases levels of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.
  
  eliglustat and fluphenazine both increase QTc interval. Use Caution/Monitor.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Monitor Closely (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

• enalapril

  Minor (1)fluphenazine increases effects of enalapril by unspecified interaction mechanism. Minor/Significance Unknown.

• encorafenib

  Monitor Closely (1)encorafenib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• entrectinib

  Monitor Closely (1)entrectinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• ephedrine

  Monitor Closely (2)fluphenazine, ephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine

  Monitor Closely (3)fluphenazine, epinephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.
  
  fluphenazine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)epinephrine and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• epinephrine racemic

  Monitor Closely (2)fluphenazine decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.
  
  fluphenazine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)epinephrine racemic and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• ergoloid mesylates

  Monitor Closely (1)ergoloid mesylates, fluphenazine. 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, fluphenazine. 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

  Monitor Closely (1)eribulin and fluphenazine both increase QTc interval. Use Caution/Monitor.

• erythromycin base

  Serious - Use Alternative (1)fluphenazine and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Serious - Use Alternative (1)fluphenazine and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Serious - Use Alternative (1)fluphenazine and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin stearate

  Serious - Use Alternative (1)fluphenazine and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.

• escitalopram

  Monitor Closely (1)escitalopram increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.

• esketamine intranasal

  Monitor Closely (1)esketamine intranasal, fluphenazine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• estazolam

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

• ethanol

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

• etomidate

  Monitor Closely (1)etomidate and fluphenazine both increase sedation. Use Caution/Monitor.

• eucalyptus

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

• fedratinib

  Monitor Closely (1)fedratinib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.

• fenfluramine

  Monitor Closely (2)fluphenazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• fentanyl

  Monitor Closely (1)fentanyl, fluphenazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (1)fentanyl, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl intranasal

  Serious - Use Alternative (1)fentanyl intranasal, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transdermal

  Serious - Use Alternative (1)fentanyl transdermal, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transmucosal

  Serious - Use Alternative (1)fentanyl transmucosal, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fesoterodine

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

• fexinidazole

  Serious - Use Alternative (1)fexinidazole and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.

• fezolinetant

  Contraindicated (1)fluphenazine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

• fingolimod

  Monitor Closely (1)fingolimod and fluphenazine both increase QTc interval. Use Caution/Monitor.

• flavoxate

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

• flecainide

  Monitor Closely (1)fluphenazine and flecainide both increase QTc interval. Modify Therapy/Monitor Closely.

• flibanserin

  Monitor Closely (1)flibanserin, fluphenazine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. 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

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

• fluoxetine

  Serious - Use Alternative (2)fluphenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  fluoxetine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• flurazepam

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

• fluvoxamine

  Monitor Closely (1)fluvoxamine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• formoterol

  Monitor Closely (1)fluphenazine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.

• foscarnet

  Monitor Closely (1)fluphenazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

• fosinopril

  Minor (1)fluphenazine increases effects of fosinopril by unspecified interaction mechanism. Minor/Significance Unknown.

• fostemsavir

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

• frovatriptan

  Monitor Closely (1)frovatriptan, fluphenazine. 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).

• ganaxolone

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

• gemifloxacin

  Monitor Closely (1)gemifloxacin and fluphenazine both increase QTc interval. Use Caution/Monitor.

• gilteritinib

  Monitor Closely (1)gilteritinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• givosiran

  Serious - Use Alternative (1)givosiran will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.

• glycopyrrolate

  Monitor Closely (2)fluphenazine increases toxicity of glycopyrrolate by unknown mechanism. Use Caution/Monitor.
  
  fluphenazine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

• glycopyrrolate inhaled

  Monitor Closely (4)glycopyrrolate inhaled decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  glycopyrrolate inhaled decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  fluphenazine increases toxicity of glycopyrrolate inhaled by unknown mechanism. Use Caution/Monitor.

• glycopyrronium tosylate topical

  Monitor Closely (1)glycopyrronium tosylate topical, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.

• granisetron

  Monitor Closely (1)granisetron and fluphenazine both increase QTc interval. Use Caution/Monitor.

• guanfacine

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

• haloperidol

  Monitor Closely (2)fluphenazine and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and haloperidol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)haloperidol will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• henbane

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

• homatropine

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

• hydrocodone

  Serious - Use Alternative (1)hydrocodone, fluphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).

• hydromorphone

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

• hydroxychloroquine sulfate

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

• hydroxyzine

  Monitor Closely (2)hydroxyzine and fluphenazine both increase sedation. Use Caution/Monitor.
  
  hydroxyzine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• hyoscyamine

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

• hyoscyamine spray

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

• ibutilide

  Contraindicated (1)fluphenazine and ibutilide both increase QTc interval. Contraindicated.

• iloperidone

  Monitor Closely (3)fluphenazine and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluphenazine and iloperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and iloperidone both increase sedation. Use Caution/Monitor.

• imatinib

  Minor (1)imatinib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• imidapril

  Minor (1)fluphenazine increases effects of imidapril by unspecified interaction mechanism. Minor/Significance Unknown.

• imipramine

  Monitor Closely (1)fluphenazine and imipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and imipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)imipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  imipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• incobotulinumtoxinA

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

• indapamide

  Contraindicated (1)fluphenazine and indapamide both increase QTc interval. Contraindicated.

• insulin degludec

  Monitor Closely (1)fluphenazine decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.

• insulin degludec/insulin aspart

  Monitor Closely (1)fluphenazine decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.

• insulin inhaled

  Monitor Closely (1)fluphenazine decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.

• ipratropium

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

• isoflurane

  Monitor Closely (1)isoflurane and fluphenazine both increase QTc interval. Use Caution/Monitor.

• isoproterenol

  Monitor Closely (2)fluphenazine, isoproterenol. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• itraconazole

  Monitor Closely (1)itraconazole and fluphenazine both increase QTc interval. Use Caution/Monitor.

• ivosidenib

  Serious - Use Alternative (1)ivosidenib and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.

• ketoconazole

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

• ketotifen, ophthalmic

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

• lapatinib

  Monitor Closely (1)fluphenazine and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.

• lasmiditan

  Monitor Closely (1)lasmiditan, fluphenazine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• lefamulin

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

• lemborexant

  Monitor Closely (1)lemborexant, fluphenazine. 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.

• levalbuterol

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

• levodopa

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

• levodopa inhaled

  Serious - Use Alternative (1)fluphenazine decreases effects of levodopa inhaled by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Phenothiazine/1st generation antipsychotics inhibit dopamine D2 receptors in varying degrees.

• levofloxacin

  Monitor Closely (1)fluphenazine and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

• levoketoconazole

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

• levomilnacipran

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

• linezolid

  Monitor Closely (1)linezolid, fluphenazine. 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)fluphenazine, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.

• lisdexamfetamine

  Monitor Closely (2)fluphenazine, lisdexamfetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lisinopril

  Minor (1)fluphenazine increases effects of lisinopril by unspecified interaction mechanism. Minor/Significance Unknown.

• lisuride

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

• lithium

  Monitor Closely (3)lithium, fluphenazine. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved.
  
  lithium, fluphenazine. 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).
  
  lithium and fluphenazine both increase QTc interval. Use Caution/Monitor.

• lofepramine

  Monitor Closely (1)fluphenazine and lofepramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and lofepramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)lofepramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  lofepramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• lofexidine

  Monitor Closely (1)fluphenazine and lofexidine both increase sedation. Use Caution/Monitor.

• loprazolam

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

• lorazepam

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

• lorcaserin

  Monitor Closely (2)lorcaserin will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  lorcaserin, fluphenazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

• lormetazepam

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

• loxapine

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

• loxapine inhaled

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

• lumefantrine

  Monitor Closely (1)lumefantrine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

• lurasidone

  Monitor Closely (1)lurasidone, fluphenazine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• macimorelin

  Serious - Use Alternative (1)macimorelin and fluphenazine 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 (1)fluphenazine and maprotiline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and maprotiline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)maprotiline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  maprotiline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• maraviroc

  Minor (1)maraviroc will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• marijuana

  Monitor Closely (1)fluphenazine and marijuana both increase sedation. Use Caution/Monitor.Minor (1)marijuana will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• meclizine

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

• melatonin

  Monitor Closely (1)fluphenazine and melatonin both increase sedation. Use Caution/Monitor.

• meperidine

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

• meprobamate

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

• metaproterenol

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

• metaxalone

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

• metformin

  Monitor Closely (1)fluphenazine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.

• methadone

  Monitor Closely (3)methadone, fluphenazine. 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).
  
  fluphenazine and methadone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  methadone and fluphenazine both increase sedation. Use Caution/Monitor.

• methamphetamine

  Monitor Closely (2)fluphenazine, methamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methocarbamol

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

• methoxsalen

  Monitor Closely (1)methoxsalen, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

• methscopolamine

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

• methyl aminolevulinate

  Serious - Use Alternative (1)fluphenazine, methyl aminolevulinate. Either increases levels of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.

• methyldopa

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

• methylenedioxymethamphetamine

  Monitor Closely (2)fluphenazine, methylenedioxymethamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methylergonovine

  Monitor Closely (1)methylergonovine, fluphenazine. 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 (2)fluphenazine, methylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.

• metoclopramide

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

• metoclopramide intranasal

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

• metrizamide

  Contraindicated (1)fluphenazine, metrizamide. Mechanism: unknown. Contraindicated. Risk of seizure. D/C phenothiazine 24h before admin. of metrizamide.

• metyrapone

  Minor (1)fluphenazine decreases effects of metyrapone by unspecified interaction mechanism. Minor/Significance Unknown.

• metyrosine

  Minor (1)metyrosine increases toxicity of fluphenazine by pharmacodynamic synergism. Minor/Significance Unknown. Increased extrapyramidal symptoms.

• midazolam

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

• midazolam intranasal

  Monitor Closely (1)midazolam intranasal, fluphenazine. 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 (2)fluphenazine, midodrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mifepristone

  Monitor Closely (1)mifepristone, fluphenazine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.

• milnacipran

  Monitor Closely (1)milnacipran, fluphenazine. 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).

• mirabegron

  Monitor Closely (1)mirabegron will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• mirtazapine

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

• mobocertinib

  Serious - Use Alternative (1)mobocertinib and fluphenazine 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)fluphenazine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• moexipril

  Minor (1)fluphenazine increases effects of moexipril by unspecified interaction mechanism. Minor/Significance Unknown.

• morphine

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

• motherwort

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

• moxifloxacin

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

• moxonidine

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

• nabilone

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

• nalbuphine

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

• naratriptan

  Monitor Closely (1)naratriptan, fluphenazine. 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).

• nilotinib

  Serious - Use Alternative (1)fluphenazine and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)nilotinib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• norepinephrine

  Monitor Closely (2)fluphenazine, norepinephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nortriptyline

  Monitor Closely (1)fluphenazine and nortriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and nortriptyline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)nortriptyline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  nortriptyline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• octreotide

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

• octreotide (Antidote)

  Serious - Use Alternative (1)fluphenazine and octreotide (Antidote) both increase QTc interval. Avoid or Use Alternate Drug.

• ofloxacin

  Monitor Closely (1)fluphenazine and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

• olanzapine

  Monitor Closely (3)olanzapine and fluphenazine both increase QTc interval. Use Caution/Monitor.
  
  fluphenazine and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and olanzapine both increase sedation. Use Caution/Monitor.

• oliceridine

  Monitor Closely (1)oliceridine, fluphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).

• olodaterol inhaled

  Monitor Closely (1)fluphenazine 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

• olopatadine intranasal

  Serious - Use Alternative (1)fluphenazine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• onabotulinumtoxinA

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

• ondansetron

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

• orphenadrine

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

• osilodrostat

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

• osimertinib

  Monitor Closely (1)osimertinib and fluphenazine 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 and fluphenazine both increase QTc interval. Use Caution/Monitor.

• oxazepam

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

• oxybutynin

  Monitor Closely (3)oxybutynin decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.

• oxybutynin topical

  Monitor Closely (3)oxybutynin topical decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin topical decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin topical increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.

• oxybutynin transdermal

  Monitor Closely (3)oxybutynin transdermal decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  oxybutynin transdermal decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin transdermal increases toxicity of fluphenazine by unspecified interaction mechanism. Minor/Significance Unknown.

• oxycodone

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

• oxymorphone

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

• ozanimod

  Monitor Closely (1)ozanimod and fluphenazine 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)fluphenazine and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluphenazine and paliperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and paliperidone both increase sedation. Use Caution/Monitor.

• pancuronium

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

• papaveretum

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

• papaverine

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

• parecoxib

  Minor (1)parecoxib will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• paroxetine

  Monitor Closely (1)paroxetine, fluphenazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Serious - Use Alternative (2)fluphenazine and paroxetine both increase QTc interval. Avoid or Use Alternate Drug.
  
  paroxetine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

• pasireotide

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

• pazopanib

  Monitor Closely (1)fluphenazine and pazopanib both increase QTc interval. Use Caution/Monitor.

• pentamidine

  Contraindicated (1)fluphenazine and pentamidine both increase QTc interval. Contraindicated.

• pentazocine

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

• pentobarbital

  Monitor Closely (1)pentobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• perindopril

  Minor (1)fluphenazine increases effects of perindopril by unspecified interaction mechanism. Minor/Significance Unknown.

• perphenazine

  Monitor Closely (2)fluphenazine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)perphenazine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• phendimetrazine

  Monitor Closely (2)fluphenazine, phendimetrazine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenelzine

  Monitor Closely (1)phenelzine, fluphenazine. 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 (1)phenobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• phentermine

  Monitor Closely (2)fluphenazine, phentermine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine

  Monitor Closely (2)fluphenazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine PO

  Monitor Closely (2)fluphenazine, phenylephrine PO. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• pholcodine

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

• pimozide

  Contraindicated (1)fluphenazine and pimozide both increase QTc interval. Contraindicated.Monitor Closely (2)fluphenazine and pimozide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and pimozide both increase sedation. Use Caution/Monitor.

• pirbuterol

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

• porfimer

  Monitor Closely (1)fluphenazine, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

• posaconazole

  Monitor Closely (1)fluphenazine and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• pralidoxime

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

• pramipexole

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

• primaquine

  Monitor Closely (1)primaquine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• primidone

  Monitor Closely (1)primidone and fluphenazine both increase sedation. Use Caution/Monitor.

• procainamide

  Contraindicated (1)fluphenazine and procainamide both increase QTc interval. Contraindicated.

• procarbazine

  Monitor Closely (2)procarbazine, fluphenazine. 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).
  
  procarbazine, fluphenazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Excessive sedation.

• prochlorperazine

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

• promazine

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

• promethazine

  Monitor Closely (3)promethazine, fluphenazine. 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).
  
  fluphenazine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  promethazine and fluphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

• propafenone

  Monitor Closely (1)propafenone will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• propantheline

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

• propofol

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

• propylhexedrine

  Monitor Closely (2)fluphenazine, propylhexedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• protriptyline

  Monitor Closely (1)fluphenazine and protriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and protriptyline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)protriptyline, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  protriptyline, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• pseudoephedrine

  Monitor Closely (1)fluphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• pyrimethamine

  Minor (1)pyrimethamine increases levels of fluphenazine by decreasing metabolism. Minor/Significance Unknown.

• quazepam

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

• quetiapine

  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.

• quinacrine

  Minor (1)quinacrine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• quinapril

  Minor (1)fluphenazine increases effects of quinapril by unspecified interaction mechanism. Minor/Significance Unknown.

• quinidine

  Contraindicated (1)fluphenazine and quinidine both increase QTc interval. Contraindicated.Monitor Closely (1)quinidine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)quinidine, fluphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.

• quinine

  Monitor Closely (1)fluphenazine and quinine both increase QTc interval. Use Caution/Monitor.

• ramelteon

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

• ramipril

  Minor (1)fluphenazine increases effects of ramipril by unspecified interaction mechanism. Minor/Significance Unknown.

• ranolazine

  Monitor Closely (1)fluphenazine and ranolazine both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)ranolazine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• rapacuronium

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

• remimazolam

  Monitor Closely (1)remimazolam, fluphenazine. 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.

• ribociclib

  Monitor Closely (1)ribociclib increases toxicity of fluphenazine by QTc interval. Use Caution/Monitor.

• rimabotulinumtoxinB

  Monitor Closely (1)fluphenazine increases effects of rimabotulinumtoxinB by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• risperidone

  Monitor Closely (3)fluphenazine and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.
  
  fluphenazine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and risperidone both increase sedation. Use Caution/Monitor.

• ritonavir

  Minor (1)ritonavir will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• rizatriptan

  Monitor Closely (1)rizatriptan, fluphenazine. 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).

• rocuronium

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

• rolapitant

  Monitor Closely (1)rolapitant will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.

• romidepsin

  Monitor Closely (1)fluphenazine and romidepsin both increase QTc interval. Modify Therapy/Monitor Closely.

• ropinirole

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

• safinamide

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

• salmeterol

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

• saquinavir

  Serious - Use Alternative (1)saquinavir increases levels of fluphenazine by QTc interval. Avoid or Use Alternate Drug. Potential for increased toxicity. .

• scopolamine

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

• scullcap

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

• secobarbital

  Monitor Closely (1)secobarbital and fluphenazine both increase sedation. Use Caution/Monitor.

• selegiline

  Monitor Closely (1)selegiline, fluphenazine. 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, fluphenazine. 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 fluphenazine by QTc interval. Use Caution/Monitor.

• serdexmethylphenidate/dexmethylphenidate

  Monitor Closely (1)fluphenazine, serdexmethylphenidate/dexmethylphenidate. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• sertraline

  Minor (1)sertraline will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• sevoflurane

  Monitor Closely (2)sevoflurane and fluphenazine both increase sedation. Use Caution/Monitor.
  
  sevoflurane and fluphenazine both increase QTc interval. Use Caution/Monitor.

• shepherd's purse

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

• siponimod

  Monitor Closely (1)siponimod and fluphenazine both increase QTc interval. Use Caution/Monitor.

• smoking

  Monitor Closely (1)smoking decreases levels of fluphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

• sodium oxybate

  Serious - Use Alternative (1)fluphenazine, 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 (1)sodium sulfate/?magnesium sulfate/potassium chloride increases effects of fluphenazine 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 (1)sodium sulfate/potassium sulfate/magnesium sulfate increases effects of fluphenazine 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 (4)solifenacin decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  solifenacin decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
  
  solifenacin and fluphenazine both increase QTc interval. Use Caution/Monitor.

• sorafenib

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

• sotalol

  Contraindicated (1)fluphenazine and sotalol both increase QTc interval. Contraindicated.

• stiripentol

  Monitor Closely (1)stiripentol, fluphenazine. 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

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

• sufentanil SL

  Serious - Use Alternative (1)sufentanil SL, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• sulfamethoxazole

  Monitor Closely (1)fluphenazine and sulfamethoxazole both increase QTc interval. Modify Therapy/Monitor Closely.

• sumatriptan

  Monitor Closely (1)sumatriptan, fluphenazine. 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, fluphenazine. 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)sunitinib and fluphenazine both increase QTc interval. Use Caution/Monitor.

• tacrolimus

  Monitor Closely (1)tacrolimus and fluphenazine both increase QTc interval. Use Caution/Monitor.

• tapentadol

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

• teduglutide

  Monitor Closely (1)teduglutide increases levels of fluphenazine by Other (see comment). Use Caution/Monitor. Comment: Teduglutide may increase absorption of concomitant PO medications; caution with with drugs requiring titration or those with a narrow therapeutic index; dose adjustment may be necessary.

• telavancin

  Monitor Closely (1)fluphenazine and telavancin both increase QTc interval. Modify Therapy/Monitor Closely.

• temazepam

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

• terbinafine

  Monitor Closely (1)terbinafine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.

• terbutaline

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

• tetrabenazine

  Monitor Closely (1)fluphenazine and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)tetrabenazine and fluphenazine both increase QTc interval. Avoid or Use Alternate Drug.

• thioridazine

  Monitor Closely (2)fluphenazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.
  
  fluphenazine and thioridazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)thioridazine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• thiothixene

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

• tiotropium

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

• tipranavir

  Minor (1)tipranavir will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• tobacco use

  Monitor Closely (1)tobacco use decreases levels of fluphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

• tolterodine

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

• topiramate

  Monitor Closely (1)fluphenazine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• tramadol

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

• trandolapril

  Minor (1)fluphenazine increases effects of trandolapril by unspecified interaction mechanism. Minor/Significance Unknown.

• tranylcypromine

  Monitor Closely (1)tranylcypromine, fluphenazine. 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)fluphenazine and trazodone both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and trazodone both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)trazodone, fluphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.
  
  trazodone, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

• tretinoin

  Serious - Use Alternative (1)fluphenazine, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• tretinoin topical

  Serious - Use Alternative (1)fluphenazine, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• triazolam

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

• triclofos

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

• trifluoperazine

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

• trihexyphenidyl

  Monitor Closely (2)trihexyphenidyl decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  fluphenazine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

• trimethoprim

  Monitor Closely (1)fluphenazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

• trimipramine

  Monitor Closely (1)fluphenazine and trimipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and trimipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)trimipramine, fluphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.
  
  trimipramine, fluphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

• triprolidine

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

• tropisetron

  Monitor Closely (1)fluphenazine and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely.

• trospium chloride

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

• umeclidinium bromide/vilanterol inhaled

  Serious - Use Alternative (1)fluphenazine increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

• valbenazine

  Monitor Closely (1)valbenazine and fluphenazine both increase QTc interval. Use Caution/Monitor.

• vecuronium

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

• venlafaxine

  Monitor Closely (2)venlafaxine, fluphenazine. 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).
  
  venlafaxine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.

• vilanterol/fluticasone furoate inhaled

  Serious - Use Alternative (1)fluphenazine 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, fluphenazine. 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).

• voriconazole

  Monitor Closely (1)fluphenazine and voriconazole both increase QTc interval. Modify Therapy/Monitor Closely.

• vorinostat

  Monitor Closely (1)vorinostat and fluphenazine both increase QTc interval. Use Caution/Monitor.

• xylometazoline

  Monitor Closely (2)fluphenazine, xylometazoline. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• yohimbe

  Serious - Use Alternative (1)yohimbe decreases effects of fluphenazine by pharmacodynamic antagonism. Contraindicated.

• yohimbine

  Monitor Closely (2)fluphenazine, yohimbine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
  
  fluphenazine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ziconotide

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

• ziprasidone

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

• zolmitriptan

  Monitor Closely (1)zolmitriptan, fluphenazine. 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).

• zolpidem

  Monitor Closely (1)fluphenazine will increase the level or effect of zolpidem by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Additive effect of decreased alertness and psychomotor performance

• zotepine

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