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.Serious - Use Alternative (1)hydrocodone, haloperidol. 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.hydromorphoneMonitor Closely (2)haloperidol 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.hydroxychloroquine sulfateSerious - Use Alternative (1)hydroxychloroquine sulfate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.hydroxyzineMonitor Closely (2)hydroxyzine and haloperidol both increase QTc interval. Use Caution/Monitor. hydroxyzine and haloperidol both increase sedation. Use Caution/Monitor.hyoscyamineMonitor Closely (3)hyoscyamine 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 sprayMonitor Closely (3)haloperidol 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.ibrutinibMonitor Closely (1)haloperidol 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.ibutilideContraindicated (1)haloperidol and ibutilide both increase QTc interval. Contraindicated.idelalisibSerious - Use Alternative (1)idelalisib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substratesifosfamideMonitor Closely (1)haloperidol 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.iloperidoneMonitor Closely (5)haloperidol will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. haloperidol and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely. haloperidol and iloperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. 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.imatinibMonitor Closely (1)imatinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.imipramineMonitor Closely (1)haloperidol and imipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)imipramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. haloperidol will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.incobotulinumtoxinAMonitor Closely (1)haloperidol, 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, inhaledMonitor Closely (1)indacaterol, 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.indapamideContraindicated (1)haloperidol and indapamide both increase QTc interval. Contraindicated.indinavirSerious - Use Alternative (1)indinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.indomethacinMinor (1)indomethacin increases toxicity of haloperidol by unknown mechanism. Minor/Significance Unknown.infigratinibSerious - Use Alternative (1)haloperidol will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.inotuzumabSerious - Use Alternative (1)inotuzumab and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. If unable to avoid concomitant use, obtain ECGs and electrolytes before and after initiation of any drug known to prolong QTc, and periodically monitor as clinically indicated during treatment.ipratropiumMonitor Closely (3)ipratropium 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.irinotecanMinor (1)haloperidol will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.irinotecan liposomalMinor (1)haloperidol will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.isavuconazonium sulfateMonitor Closely (1)haloperidol will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isofluraneSerious - Use Alternative (1)isoflurane and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.isoniazidMonitor Closely (1)isoniazid will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isoproterenolMonitor Closely (1)haloperidol increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.isradipineMonitor Closely (1)haloperidol and isradipine both increase QTc interval. Use Caution/Monitor.istradefyllineMonitor Closely (1)istradefylline 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.itraconazoleMonitor Closely (2)itraconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. haloperidol and itraconazole both increase QTc interval. Modify Therapy/Monitor Closely.ivabradineSerious - Use Alternative (1)haloperidol will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.ivacaftorMonitor Closely (1)haloperidol 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.ivosidenibMonitor Closely (1)haloperidol will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.Serious - Use Alternative (2)ivosidenib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation. ivosidenib will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.ketamineMonitor Closely (1)ketamine and haloperidol both increase sedation. Use Caution/Monitor.ketoconazoleMonitor Closely (1)ketoconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)haloperidol and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.ketotifen, ophthalmicMonitor Closely (1)haloperidol and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.lapatinibMonitor Closely (1)haloperidol and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.larotrectinibMinor (1)larotrectinib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lasmiditanMonitor Closely (1)lasmiditan, haloperidol. 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.lefamulinContraindicated (1)lefamulin will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.lemborexantMonitor Closely (1)lemborexant, haloperidol. 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.Serious - Use Alternative (1)haloperidol will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.lenacapavirMonitor Closely (1)lenacapavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.lenvatinibMonitor Closely (1)haloperidol and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.letermovirMonitor Closely (1)letermovir increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.leuprolideMonitor Closely (1)leuprolide increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.levalbuterolMonitor Closely (1)haloperidol increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.levamlodipineMonitor Closely (1)haloperidol will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.levodopaSerious - Use Alternative (1)haloperidol decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.levofloxacinMonitor Closely (1)haloperidol and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.levoketoconazoleMonitor Closely (1)levoketoconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)haloperidol and levoketoconazole both increase QTc interval. Avoid or Use Alternate Drug.levomilnacipranMonitor Closely (1)levomilnacipran, 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).levorphanolMonitor Closely (1)levorphanol and haloperidol both increase sedation. Use Caution/Monitor.linezolidMonitor Closely (1)linezolid, 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).lisdexamfetamineMonitor Closely (1)haloperidol increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lisurideSerious - Use Alternative (1)haloperidol decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.lithiumMonitor Closely (3)lithium, haloperidol. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved. lithium, 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). lithium and haloperidol both increase QTc interval. Use Caution/Monitor.lofepramineMonitor Closely (2)haloperidol will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. haloperidol and lofepramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)lofepramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.lofexidineMonitor Closely (1)haloperidol and lofexidine both increase sedation. Use Caution/Monitor.lomitapideContraindicated (1)haloperidol increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.lonafarnibContraindicated (1)haloperidol will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated. lopinavirSerious - Use Alternative (1)lopinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.loprazolamMonitor Closely (1)loprazolam and haloperidol both increase sedation. Use Caution/Monitor.loratadineMinor (1)haloperidol will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.lorazepamMonitor Closely (1)lorazepam and haloperidol both increase sedation. Use Caution/Monitor.lorcaserinMonitor Closely (2)lorcaserin will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. lorcaserin, 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).lorlatinibMonitor Closely