metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.efavirenzefavirenz will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.efavirenz and haloperidol both increase QTc interval. Use Caution/Monitor.elagolixelagolix decreases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.eletriptaneletriptan, haloperidol. 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).eliglustateliglustat increases levels of haloperidol 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.elvitegravir/cobicistat/emtricitabine/tenofovir DFelvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of haloperidol 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.encorafenibencorafenib, haloperidol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.enzalutamideenzalutamide will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ephedrinehaloperidol increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrinehaloperidol increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrine racemichaloperidol increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ergoloid mesylatesergoloid mesylates, haloperidol. 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).ergotamineergotamine, haloperidol. 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).escitalopramhaloperidol and escitalopram both increase QTc interval. Use Caution/Monitor.escitalopram increases toxicity of haloperidol by QTc interval. Use Caution/Monitor.esketamine intranasalesketamine intranasal, haloperidol. Either increases toxicity of the other by sedation. Use Caution/Monitor.estazolamestazolam and haloperidol both increase sedation. Use Caution/Monitor.ethanolhaloperidol and ethanol both increase sedation. Use Caution/Monitor.etomidateetomidate and haloperidol both increase sedation. Use Caution/Monitor.etravirineetravirine will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ezogabineezogabine, haloperidol. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.fedratinibfedratinib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.fedratinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.fenfluraminehaloperidol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fentanylfentanyl, haloperidol. 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).fesoterodinefesoterodine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.fesoterodine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.finerenonehaloperidol will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.flavoxateflavoxate decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.flavoxate decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.flecainidehaloperidol will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised.flecainide and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.flibanserinflibanserin, haloperidol. 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).fluoxetinefluoxetine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.fluphenazinefluphenazine 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.flurazepamflurazepam and haloperidol both increase sedation. Use Caution/Monitor.fluvoxaminefluvoxamine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.formoterolhaloperidol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.foscarnetfoscarnet and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.fostemsavirhaloperidol and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.frovatriptanfrovatriptan, haloperidol. 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).gadobenategadobenate and haloperidol both increase QTc interval. Use Caution/Monitor.ganaxolonehaloperidol and ganaxolone both increase sedation. Use Caution/Monitor.gemifloxacinhaloperidol and gemifloxacin both increase QTc interval. Use Caution/Monitor.gemtuzumabhaloperidol and gemtuzumab both increase QTc interval. Use Caution/Monitor.gilteritinibgilteritinib and haloperidol both increase QTc interval. Use Caution/Monitor.glycerol phenylbutyratehaloperidol decreases effects of glycerol phenylbutyrate by Other (see comment). Use Caution/Monitor. Comment: Haloperidol may induce hyperammonemia; monitor ammonia levels closely when coadministered with glycerol phenylbutyrate.glycopyrrolatehaloperidol increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.glycopyrrolate inhaledglycopyrrolate inhaled decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.glycopyrrolate inhaled decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.glycopyrronium tosylate topicalglycopyrronium tosylate topical, haloperidol. 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.goserelingoserelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.granisetrongranisetron and haloperidol both increase QTc interval. Use Caution/Monitor.guanfacineguanfacine, haloperidol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.haloperidol will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.henbanehenbane decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.henbane decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.histrelinhistrelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.homatropinehomatropine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.homatropine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hydrocodonehaloperidol will increase the level or effect of hydrocodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.hydromorphonehaloperidol will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.hydromorphone and haloperidol both increase sedation. Use Caution/Monitor.hydroxyzinehydroxyzine and haloperidol both increase sedation. Use Caution/Monitor.hydroxyzine and haloperidol both increase QTc interval. Use Caution/Monitor.hyoscyaminehyoscyamine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.hyoscyamine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine sprayhaloperidol increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine spray decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.hyoscyamine spray decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.ibrutinibhaloperidol increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate CYP3A4 inhibitors, reduce ibrutinib dose to 280 mg qDay (B-cell malignancies) or 420 mg qDay (graft versus host disease). After CYP3A inhibitor discontinuation, resume previous dose of ibrutinib.ifosfamidehaloperidol decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of a CYP3A4 inhibitor may decrease metabolism of ifosfamide, potentially reducing ifosfamide therapeutic effects.iloperidonehaloperidol will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.haloperidol and iloperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.haloperidol and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely.haloperidol and iloperidone both increase sedation. Use Caution/Monitor.iloperidone increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.imatinibimatinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.imipraminehaloperidol and imipramine both increase sedation. Use Caution/Monitor.incobotulinumtoxinAhaloperidol, 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, inhaledindacaterol, inhaled, haloperidol. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.ipratropiumipratropium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.ipratropium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.isavuconazonium sulfatehaloperidol will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isoniazidisoniazid will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isoproterenolhaloperidol increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.isradipinehaloperidol and isradipine both increase QTc interval. Use Caution/Monitor.istradefyllineistradefylline will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.itraconazolehaloperidol and itraconazole both increase QTc interval. Modify Therapy/Monitor Closely.itraconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ivacaftorhaloperidol will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with moderate CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.ivosidenibhaloperidol will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with