increases effects of fosinopril by unspecified interaction mechanism. Minor/Significance Unknown.frovatriptanMonitor Closely (1)frovatriptan, perphenazine. 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).galantamineMinor (1)perphenazine will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.ganaxoloneMonitor Closely (1)perphenazine and ganaxolone both increase sedation. Use Caution/Monitor.gemifloxacinMonitor Closely (1)gemifloxacin and perphenazine both increase QTc interval. Use Caution/Monitor.gilteritinibMonitor Closely (1)gilteritinib and perphenazine both increase QTc interval. Use Caution/Monitor.givosiranSerious - Use Alternative (1)givosiran will increase the level or effect of perphenazine 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.glycopyrrolateMonitor Closely (2)perphenazine increases toxicity of glycopyrrolate by unknown mechanism. Use Caution/Monitor. perphenazine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.glycopyrrolate inhaledMonitor Closely (4)glycopyrrolate inhaled decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. glycopyrrolate inhaled decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. perphenazine increases toxicity of glycopyrrolate inhaled by unknown mechanism. Use Caution/Monitor.glycopyrronium tosylate topicalMonitor Closely (1)glycopyrronium tosylate topical, perphenazine. 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.granisetronMonitor Closely (1)granisetron and perphenazine both increase QTc interval. Use Caution/Monitor.guanfacineMonitor Closely (1)guanfacine, perphenazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.haloperidolMonitor Closely (3)perphenazine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. haloperidol and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. haloperidol and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)haloperidol will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.henbaneMonitor Closely (3)henbane decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. henbane decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.homatropineMonitor Closely (3)homatropine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. homatropine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hydrocodoneMonitor Closely (1)perphenazine 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.Serious - Use Alternative (1)hydrocodone, perphenazine. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).hydromorphoneMonitor Closely (2)perphenazine will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. hydromorphone and perphenazine both increase sedation. Use Caution/Monitor.hydroxychloroquine sulfateSerious - Use Alternative (1)hydroxychloroquine sulfate and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.hydroxyzineMonitor Closely (2)hydroxyzine and perphenazine both increase sedation. Use Caution/Monitor. hydroxyzine and perphenazine both increase QTc interval. Use Caution/Monitor.hyoscyamineMonitor Closely (3)hyoscyamine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. hyoscyamine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine sprayMonitor Closely (3)perphenazine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. hyoscyamine spray decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. hyoscyamine spray decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.ibutilideContraindicated (1)perphenazine and ibutilide both increase QTc interval. Contraindicated.iloperidoneMonitor Closely (4)perphenazine will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. perphenazine and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely. iloperidone and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. iloperidone and perphenazine both increase sedation. Use Caution/Monitor.imatinibMinor (1)imatinib will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.imidaprilMinor (1)perphenazine increases effects of imidapril by unspecified interaction mechanism. Minor/Significance Unknown.imipramineMonitor Closely (2)perphenazine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. perphenazine and imipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and imipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)imipramine, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. imipramine, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.incobotulinumtoxinAMonitor Closely (1)perphenazine, 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, perphenazine. 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)perphenazine and indapamide both increase QTc interval. Contraindicated.insulin degludecMonitor Closely (1)perphenazine decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.insulin degludec/insulin aspartMonitor Closely (1)perphenazine decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.insulin inhaledMonitor Closely (1)perphenazine decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase blood glucose concentrations.ipratropiumMonitor Closely (3)ipratropium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. ipratropium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.isocarboxazidSerious - Use Alternative (1)isocarboxazid, perphenazine. Other (see comment). Contraindicated. Comment: Concurrent use may prolong or intensify the hypotensive, anticholinergic, or sedative effects of isocarboxazid or perphenazine.isofluraneMonitor Closely (1)isoflurane and perphenazine both increase QTc interval. Use Caution/Monitor.isoproterenolMonitor Closely (2)perphenazine, isoproterenol. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. perphenazine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.itraconazoleSerious - Use Alternative (1)perphenazine and itraconazole both increase QTc interval. Avoid or Use Alternate Drug.ivosidenibSerious - Use Alternative (1)ivosidenib and perphenazine 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.ketamineMonitor Closely (1)ketamine and perphenazine both increase sedation. Use Caution/Monitor.ketoconazoleSerious - Use Alternative (1)perphenazine and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.ketotifen, ophthalmicMonitor Closely (1)perphenazine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.lapatinibMonitor Closely (1)perphenazine and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.lasmiditanMonitor Closely (1)lasmiditan, perphenazine. 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.lemborexantMonitor Closely (1)lemborexant, perphenazine. 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.levalbuterolMonitor Closely (1)perphenazine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.levodopaSerious - Use Alternative (1)perphenazine decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.levodopa inhaledSerious - Use Alternative (1)perphenazine decreases effects of levodopa inhaled by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Phenothiazine/1st generation antipsychotics inhibit dopamine D2 receptors in varying degrees.levofloxacinMonitor Closely (1)perphenazine and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.levoketoconazoleSerious - Use Alternative (1)perphenazine and levoketoconazole both increase QTc interval. Avoid or Use Alternate Drug.levomilnacipranMonitor Closely (1)levomilnacipran, perphenazine. 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 perphenazine both increase sedation. Use Caution/Monitor.linezolidMonitor Closely (1)linezolid, perphenazine. 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).liraglutideMonitor Closely (1)perphenazine, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.lisdexamfetamineMonitor Closely (2)perphenazine, lisdexamfetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. perphenazine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lisinoprilMinor (1)perphenazine increases effects of lisinopril by unspecified interaction mechanism. Minor/Significance Unknown.lisurideSerious - Use Alternative (1)perphenazine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.lithiumMonitor Closely (3)lithium, perphenazine. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved. lithium, perphenazine. 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 perphenazine both increase QTc interval. Use Caution/Monitor.lofepramineMonitor Closely (2)perphenazine will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. perphenazine and lofepramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and lofepramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)lofepramine, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. lofepramine, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.lofexidineMonitor Closely (1)perphenazine and lofexidine both increase sedation. Use Caution/Monitor.loprazolamMonitor Closely (1)loprazolam and perphenazine both increase sedation. Use Caution/Monitor.loratadineMinor (1)perphenazine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.lorazepamMonitor Closely (1)lorazepam and perphenazine both increase sedation. Use Caution/Monitor.lorcaserinMonitor Closely (2)lorcaserin will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. lorcaserin, perphenazine. 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 (1)perphenazine and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.lormetazepamMonitor Closely (1)lormetazepam and perphenazine both increase sedation. Use Caution/Monitor.loxapineMonitor Closely (2)loxapine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. loxapine and perphenazine both increase sedation. Use Caution/Monitor.loxapine inhaledMonitor Closely (2)loxapine inhaled and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. loxapine inhaled and perphenazine both increase sedation. Use Caution/Monitor.lumefantrineMonitor Closely (1)lumefantrine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use