(1)lorlatinib will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lormetazepamMonitor Closely (1)lormetazepam and haloperidol both increase sedation. Use Caution/Monitor.loxapineMonitor Closely (2)haloperidol and loxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. haloperidol and loxapine both increase sedation. Use Caution/Monitor.loxapine inhaledMonitor Closely (2)haloperidol and loxapine inhaled both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. haloperidol and loxapine inhaled both increase sedation. Use Caution/Monitor.lumateperoneMonitor Closely (1)haloperidol will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.lumefantrineSerious - Use Alternative (2)haloperidol and lumefantrine both increase QTc interval. Avoid or Use Alternate Drug. lumefantrine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.lurasidoneMonitor Closely (1)lurasidone, haloperidol. 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.lurbinectedinSerious - Use Alternative (1)haloperidol will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.macimorelinSerious - Use Alternative (1)macimorelin and haloperidol 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.maprotilineMonitor Closely (1)haloperidol and maprotiline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)maprotiline and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.maravirocMonitor Closely (1)maraviroc will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.marijuanaMonitor Closely (2)marijuana will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. haloperidol and marijuana both increase sedation. Use Caution/Monitor.mavacamtenMonitor Closely (1)haloperidol will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose. meclizineMonitor Closely (3)meclizine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. meclizine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor. haloperidol increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.mefloquineMonitor Closely (2)haloperidol will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. haloperidol and mefloquine both increase QTc interval. Use Caution/Monitor.melatoninMonitor Closely (1)haloperidol and melatonin both increase sedation. Use Caution/Monitor.meperidineMonitor Closely (2)meperidine, 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). meperidine and haloperidol both increase sedation. Use Caution/Monitor.meprobamateMonitor Closely (1)haloperidol and meprobamate both increase sedation. Use Caution/Monitor.metaproterenolMonitor Closely (1)haloperidol increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaxaloneMonitor Closely (1)metaxalone and haloperidol both increase sedation. Use Caution/Monitor.methadoneMonitor Closely (3)methadone, 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). haloperidol and methadone both increase QTc interval. Modify Therapy/Monitor Closely. methadone and haloperidol both increase sedation. Use Caution/Monitor.methamphetamineMonitor Closely (2)haloperidol will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. haloperidol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methocarbamolMonitor Closely (1)methocarbamol and haloperidol both increase sedation. Use Caution/Monitor.methscopolamineMonitor Closely (3)methscopolamine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. methscopolamine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor. haloperidol increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.methyldopaSerious - Use Alternative (1)haloperidol decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.methylenedioxymethamphetamineMonitor Closely (1)haloperidol increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methylergonovineMonitor Closely (1)methylergonovine, 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).methylphenidateMonitor Closely (1)haloperidol 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.metoclopramideMonitor Closely (1)haloperidol and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.metoclopramide intranasalSerious - Use Alternative (2)haloperidol, 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. haloperidol 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.metoprololMonitor Closely (1)haloperidol will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.metyrosineMinor (1)metyrosine increases effects of haloperidol by pharmacodynamic synergism. Minor/Significance Unknown.mexiletineMonitor Closely (2)haloperidol will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised haloperidol and mexiletine both increase QTc interval. Use Caution/Monitor.midazolamMonitor Closely (1)midazolam and haloperidol both increase sedation. Use Caution/Monitor.midazolam intranasalMonitor Closely (1)midazolam intranasal, haloperidol. 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.Serious - Use Alternative (1)haloperidol will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.midodrineMonitor Closely (1)haloperidol increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.mifepristoneMonitor Closely (1)mifepristone, haloperidol. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.Serious - Use Alternative (1)mifepristone will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.milnacipranMonitor Closely (1)milnacipran, 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).mirabegronMonitor Closely (1)mirabegron will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapineMonitor Closely (2)mirtazapine and haloperidol both increase QTc interval. Use Caution/Monitor. haloperidol and mirtazapine both increase sedation. Use Caution/Monitor.mitotaneMonitor Closely (1)mitotane decreases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.mobocertinibSerious - Use Alternative (2)haloperidol will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval. mobocertinib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.modafinilMonitor Closely (1)haloperidol increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.morphineMonitor Closely (2)haloperidol will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. morphine and haloperidol both increase sedation. Use Caution/Monitor.motherwortMonitor Closely (1)haloperidol and motherwort both increase sedation. Use Caution/Monitor.moxifloxacinSerious - Use Alternative (1)haloperidol and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.moxonidineMonitor Closely (1)haloperidol and moxonidine both increase sedation. Use Caution/Monitor.nabiloneMonitor Closely (1)haloperidol and nabilone both increase sedation. Use Caution/Monitor.nafcillinMonitor Closely (1)nafcillin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nalbuphineMonitor Closely (1)nalbuphine and haloperidol both increase sedation. Use Caution/Monitor.naldemedineMonitor Closely (1)haloperidol increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.naloxegolSerious - Use Alternative (1)haloperidol will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDaynaratriptanMonitor Closely (1)naratriptan, 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).nebivololMonitor Closely (1)haloperidol will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.nefazodoneMonitor Closely (1)nefazodone will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nelfinavirMonitor Closely (1)nelfinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.neratinibSerious - Use Alternative (1)haloperidol will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.nilotinibMonitor Closely (1)nilotinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)haloperidol and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.norepinephrineMonitor Closely (1)haloperidol increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.norgestrelMonitor Closely (1)haloperidol will increase the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may increase systemic concentration of norgestrel, which may increase risk for adverse effects nortriptylineMonitor Closely (1)haloperidol and nortriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)nortriptyline and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. haloperidol will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.octreotideSerious - Use Alternative (1)haloperidol and octreotide both increase QTc interval. Avoid or Use Alternate Drug.octreotide (Antidote)Serious - Use Alternative (1)haloperidol and octreotide (Antidote) both increase QTc interval. Avoid or Use Alternate Drug.ofloxacinMonitor Closely (1)haloperidol and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.olanzapineMonitor Closely (3)haloperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. haloperidol and olanzapine both increase sedation. Use Caution/Monitor. haloperidol and olanzapine both increase QTc interval. Use Caution/Monitor.olaparibSerious - Use Alternative (1)haloperidol will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.oliceridineMonitor Closely (2)haloperidol will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. oliceridine, haloperidol. 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.Minor (1)haloperidol will increase the level or effect