of haloperidol 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 sulfatesodium sulfate/potassium sulfate/magnesium sulfate increases effects of haloperidol 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.solifenacinsolifenacin decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.solifenacin decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.haloperidol and solifenacin both increase QTc interval. Use Caution/Monitor.sonidegibhaloperidol will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.sorafenibsorafenib and haloperidol both increase QTc interval. Use Caution/Monitor.sparsentanhaloperidol will increase the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No dosage adjustment needed. Monitor blood pressure, serum potassium, edema, and kidney function regularly if sparsentan is coadministered with moderate CYP3A4 inhibitors. stiripentolstiripentol, haloperidol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.stiripentol, haloperidol. 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.sufentanilsufentanil and haloperidol both increase sedation. Use Caution/Monitor.sufentanil SLhaloperidol will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.sulfamethoxazolesulfamethoxazole and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.sumatriptansumatriptan, 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).sumatriptan intranasalsumatriptan intranasal, 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).sunitinibhaloperidol and sunitinib both increase QTc interval. Use Caution/Monitor.suvorexanthaloperidol will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitorstacrolimushaloperidol and tacrolimus both increase QTc interval. Use Caution/Monitor.tadalafilhaloperidol will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events. tamoxifenhaloperidol decreases effects of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.tamsulosinhaloperidol increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.haloperidol increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.tapentadoltapentadol and haloperidol both increase sedation. Use Caution/Monitor.tazemetostattazemetostat will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimattecovirimat will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.teduglutideteduglutide increases levels of haloperidol 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.telavancinhaloperidol and telavancin both increase QTc interval. Modify Therapy/Monitor Closely.temazepamtemazepam and haloperidol both increase sedation. Use Caution/Monitor.terbinafineterbinafine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.terbutalinehaloperidol increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.tetrabenazinehaloperidol and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.tezacaftorhaloperidol will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.thioridazinethioridazine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.haloperidol and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.haloperidol and thioridazine both increase sedation. Use Caution/Monitor.thiothixenehaloperidol and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.haloperidol and thiothixene both increase sedation. Use Caution/Monitor.haloperidol and thiothixene both increase QTc interval. Use Caution/Monitor.timololhaloperidol will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.tinidazolehaloperidol will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tiotropiumtiotropium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tiotropium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.tipranavirtipranavir will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.tipranavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tofacitinibhaloperidol increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors.tolterodinetolterodine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.tolterodine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.topiramatehaloperidol and topiramate both increase sedation. Modify Therapy/Monitor Closely.trabectedinhaloperidol will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tramadoltramadol and haloperidol both increase sedation. Use Caution/Monitor.tranylcyprominetranylcypromine, 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).trazodonehaloperidol and trazodone both increase sedation. Use Caution/Monitor.triazolamtriazolam and haloperidol both increase sedation. Use Caution/Monitor.triclabendazoletriclabendazole and haloperidol both increase QTc interval. Use Caution/Monitor.triclofostriclofos and haloperidol both increase sedation. Use Caution/Monitor.trifluoperazinehaloperidol and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.haloperidol and trifluoperazine both increase sedation. Use Caution/Monitor.trihexyphenidylhaloperidol increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.trimethoprimhaloperidol and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.trimipraminehaloperidol and trimipramine both increase sedation. Use Caution/Monitor.triprolidinetriprolidine and haloperidol both increase sedation. Use Caution/Monitor.triptorelintriptorelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.tropisetronhaloperidol and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely.trospium chloridetrospium chloride decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.trospium chloride decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.valbenazinevalbenazine and haloperidol both increase QTc interval. Use Caution/Monitor.vardenafilhaloperidol and vardenafil both increase QTc interval. Use Caution/Monitor.haloperidol will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vardenafil dose may need to be reduced if coadministered with moderate or strong CYP3A4 inhibitors vecuroniumvecuronium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.vecuronium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.haloperidol increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.venlafaxinevenlafaxine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.haloperidol and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.venlafaxine, 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).vilazodonevilazodone, 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).voclosporinhaloperidol will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce voclosporin daily dosage to 15.8 mg PO in AM and 7.9 mg PO in PM.voclosporin, haloperidol. Either increases effects of the other by QTc interval. Use Caution/Monitor.voriconazolehaloperidol and voriconazole both increase QTc interval. Modify Therapy/Monitor Closely.voriconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.vorinostathaloperidol and vorinostat both increase QTc interval. Use Caution/Monitor.xylometazolinehaloperidol increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.yohimbinehaloperidol increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.zanubrutinibhaloperidol will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib (a CYP3A4 substrate) to 80 mg PO BID to when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib. ziconotidehaloperidol and ziconotide both increase sedation. Use Caution/Monitor.ziprasidonehaloperidol and ziprasidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.haloperidol and ziprasidone both increase sedation. Use Caution/Monitor.zolmitriptanzolmitriptan, 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).zotepinehaloperidol and zotepine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.haloperidol and zotepine both increase sedation. Use Caution/Monitor.Minor (44)acetazolamideacetazolamide will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.amobarbitalhaloperidol, amobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.anastrozoleanastrozole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.aripiprazolehaloperidol will increase the level or effect of aripiprazole by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.brimonidinebrimonidine increases effects of haloperidol by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.butabarbitalhaloperidol, butabarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.butalbitalhaloperidol, butalbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.chasteberrychasteberry decreases effects of haloperidol by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).chlorpromazinehaloperidol will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cyclophosphamidecyclophosphamide will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.dexfenfluraminehaloperidol will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.dextroamphetaminehaloperidol will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.dextromethorphanhaloperidol will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.donepezilhaloperidol will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.duloxetineduloxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.haloperidol will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.encainidehaloperidol will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.estradiol vaginalhaloperidol