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).eribulinSerious - Use Alternative (1)eribulin and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Potential for enhanced QTc-prolonging effects; if concurrent use is necessary then ECG monitoring is recommended.erythromycin baseSerious - Use Alternative (1)erythromycin base and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.erythromycin ethylsuccinateSerious - Use Alternative (1)erythromycin ethylsuccinate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.erythromycin lactobionateSerious - Use Alternative (1)erythromycin lactobionate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.erythromycin stearateSerious - Use Alternative (1)erythromycin stearate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.escitalopramMonitor Closely (2)escitalopram increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. haloperidol and escitalopram both increase QTc interval. Use Caution/Monitor.esketamine intranasalMonitor Closely (1)esketamine intranasal, haloperidol. Either increases toxicity of the other by sedation. Use Caution/Monitor.estazolamMonitor Closely (1)estazolam and haloperidol both increase sedation. Use Caution/Monitor.estradiol vaginalMinor (1)haloperidol will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ethanolMonitor Closely (1)haloperidol and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.etomidateMonitor Closely (1)etomidate and haloperidol both increase sedation. Use Caution/Monitor.etravirineMonitor Closely (1)etravirine will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.eucalyptusMinor (1)haloperidol and eucalyptus both increase sedation. Minor/Significance Unknown.ezogabineMonitor Closely (1)ezogabine, 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.fedratinibMonitor Closely (2)fedratinib 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.fenfluramineMonitor Closely (1)haloperidol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fentanylMonitor Closely (1)fentanyl, 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).Serious - Use Alternative (2)fentanyl, haloperidol. 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. haloperidol will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fentanyl intranasalSerious - Use Alternative (2)fentanyl intranasal, haloperidol. 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. haloperidol will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fentanyl transdermalSerious - Use Alternative (2)fentanyl transdermal, haloperidol. 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. haloperidol will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fentanyl transmucosalSerious - Use Alternative (2)fentanyl transmucosal, haloperidol. 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. haloperidol will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.fesoterodineMonitor Closely (3)fesoterodine 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.Minor (1)haloperidol will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.fexinidazoleSerious - Use Alternative (2)fexinidazole and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval. fexinidazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.finerenoneMonitor Closely (1)haloperidol 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.fingolimodSerious - Use Alternative (1)fingolimod and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.flavoxateMonitor Closely (3)flavoxate 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.flecainideMonitor Closely (2)haloperidol 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.flibanserinContraindicated (1)haloperidol will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.Monitor Closely (1)flibanserin, 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).fluconazoleSerious - Use Alternative (1)fluconazole and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.fluoxetineMonitor Closely (1)fluoxetine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)fluoxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. haloperidol will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.fluphenazineMonitor 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.flurazepamMonitor Closely (1)flurazepam and haloperidol both increase sedation. Use Caution/Monitor.fluvoxamineMonitor Closely (1)fluvoxamine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.formoterolMonitor Closely (1)haloperidol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)formoterol and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.foscarnetMonitor Closely (1)foscarnet and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.fosphenytoinSerious - Use Alternative (1)fosphenytoin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.fostemsavirMonitor Closely (1)haloperidol and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.frovatriptanMonitor Closely (1)frovatriptan, 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).gadobenateMonitor Closely (1)gadobenate and haloperidol both increase QTc interval. Use Caution/Monitor.galantamineMinor (1)haloperidol will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.ganaxoloneMonitor Closely (1)haloperidol and ganaxolone both increase sedation. Use Caution/Monitor.gemifloxacinMonitor Closely (1)haloperidol and gemifloxacin both increase QTc interval. Use Caution/Monitor.gemtuzumabMonitor Closely (1)haloperidol and gemtuzumab both increase QTc interval. Use Caution/Monitor.gilteritinibMonitor Closely (1)gilteritinib and haloperidol both increase QTc interval. Use Caution/Monitor.givosiranSerious - Use Alternative (1)givosiran will increase the level or effect of haloperidol 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.glasdegibSerious - Use Alternative (1)haloperidol and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.glycerol phenylbutyrateMonitor Closely (1)haloperidol 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.glycopyrrolateMonitor Closely (1)haloperidol increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.glycopyrrolate inhaledMonitor Closely (3)glycopyrrolate 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 topicalMonitor Closely (1)glycopyrronium 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.goserelinMonitor Closely (1)goserelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.granisetronMonitor Closely (1)granisetron and haloperidol both increase QTc interval. Use Caution/Monitor.guanfacineMonitor Closely (2)guanfacine, 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.henbaneMonitor Closely (3)henbane 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.histrelinMonitor Closely (1)histrelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.homatropineMonitor Closely (3)homatropine 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.hydrocodoneMonitor Closely (1)haloperidol will increase the level or effect of hydrocodone by affecting hepatic enzyme