decrease QTc interval. Use Caution/Monitor.hyoscyamineMonitor Closely (3)hyoscyamine decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. hyoscyamine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor. trifluoperazine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine sprayMonitor Closely (3)trifluoperazine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. hyoscyamine spray decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. hyoscyamine spray decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.ibutilideContraindicated (1)trifluoperazine and ibutilide both increase QTc interval. Contraindicated.iloperidoneMonitor Closely (3)trifluoperazine and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely. iloperidone and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. iloperidone and trifluoperazine both increase sedation. Use Caution/Monitor.imatinibMinor (1)imatinib will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.imidaprilMinor (1)trifluoperazine increases effects of imidapril by unspecified interaction mechanism. Minor/Significance Unknown.imipramineMonitor Closely (1)trifluoperazine and imipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)trifluoperazine and imipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)imipramine, trifluoperazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. imipramine, trifluoperazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.incobotulinumtoxinAMonitor Closely (1)trifluoperazine increases effects of incobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.indacaterol, inhaledMonitor Closely (1)indacaterol, inhaled, trifluoperazine. 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)trifluoperazine and indapamide both increase QTc interval. Contraindicated.insulin degludecMonitor Closely (1)trifluoperazine 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)trifluoperazine 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)trifluoperazine 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 trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. ipratropium decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor. trifluoperazine increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.isofluraneMonitor Closely (1)isoflurane and trifluoperazine both decrease QTc interval. Use Caution/Monitor.isoproterenolMonitor Closely (2)trifluoperazine, 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. trifluoperazine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.itraconazoleSerious - Use Alternative (1)trifluoperazine and itraconazole both increase QTc interval. Avoid or Use Alternate Drug.ketamineMonitor Closely (1)ketamine and trifluoperazine both increase sedation. Use Caution/Monitor.ketoconazoleSerious - Use Alternative (1)trifluoperazine and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.ketotifen, ophthalmicMonitor Closely (1)trifluoperazine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.lapatinibMonitor Closely (1)trifluoperazine and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.lasmiditanMonitor Closely (1)lasmiditan, trifluoperazine. 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, trifluoperazine. 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)trifluoperazine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.levodopaSerious - Use Alternative (1)trifluoperazine decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.levodopa inhaledSerious - Use Alternative (1)trifluoperazine 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)trifluoperazine and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.levoketoconazoleSerious - Use Alternative (1)trifluoperazine and levoketoconazole both increase QTc interval. Avoid or Use Alternate Drug.levomilnacipranMonitor Closely (1)levomilnacipran, trifluoperazine. 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 trifluoperazine both increase sedation. Use Caution/Monitor.linezolidMonitor Closely (1)linezolid, trifluoperazine. 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)trifluoperazine, 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)trifluoperazine, 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. trifluoperazine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lisinoprilMinor (1)trifluoperazine increases effects of lisinopril by unspecified interaction mechanism. Minor/Significance Unknown.lisurideSerious - Use Alternative (1)trifluoperazine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.lithiumMonitor Closely (3)lithium, trifluoperazine. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved. lithium, trifluoperazine. 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 trifluoperazine both decrease QTc interval. Use Caution/Monitor.lofepramineMonitor Closely (1)trifluoperazine and lofepramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)trifluoperazine and lofepramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)lofepramine, trifluoperazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. lofepramine, trifluoperazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.lofexidineMonitor Closely (1)trifluoperazine and lofexidine both increase sedation. Use Caution/Monitor.loprazolamMonitor Closely (1)loprazolam and trifluoperazine both increase sedation. Use Caution/Monitor.lorazepamMonitor Closely (1)lorazepam and trifluoperazine both increase sedation. Use Caution/Monitor.lorcaserinMonitor Closely (1)lorcaserin, trifluoperazine. 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).lormetazepamMonitor Closely (1)lormetazepam and trifluoperazine both increase sedation. Use Caution/Monitor.loxapineMonitor Closely (2)loxapine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. loxapine and trifluoperazine both increase sedation. Use Caution/Monitor.loxapine inhaledMonitor Closely (2)loxapine inhaled and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. loxapine inhaled and trifluoperazine both increase sedation. Use Caution/Monitor.lumefantrineMonitor Closely (1)lumefantrine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)trifluoperazine and lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.lurasidoneMonitor Closely (1)lurasidone, trifluoperazine. 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.maprotilineMonitor Closely (1)trifluoperazine and maprotiline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)trifluoperazine and maprotiline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)maprotiline, trifluoperazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. maprotiline, trifluoperazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.maravirocMinor (1)maraviroc will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.marijuanaMonitor Closely (1)trifluoperazine and marijuana both increase sedation. Use Caution/Monitor.Minor (1)marijuana will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.meclizineMonitor Closely (3)meclizine decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. meclizine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor. trifluoperazine increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.melatoninMonitor Closely (1)trifluoperazine and melatonin both increase sedation. Use Caution/Monitor.meperidineMonitor Closely (2)meperidine, trifluoperazine. 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 trifluoperazine both increase sedation. Use Caution/Monitor.meprobamateMonitor Closely (1)trifluoperazine and meprobamate both increase sedation. Use Caution/Monitor.metaproterenolMonitor Closely (1)trifluoperazine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaxaloneMonitor Closely (1)metaxalone and trifluoperazine both increase sedation. Use Caution/Monitor.metforminMonitor Closely (1)trifluoperazine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.methadoneMonitor Closely (3)methadone, trifluoperazine. 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). trifluoperazine and methadone both increase QTc interval. Modify Therapy/Monitor Closely. methadone and trifluoperazine both increase sedation. Use Caution/Monitor.methamphetamineMonitor Closely (2)trifluoperazine, methamphetamine. 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. trifluoperazine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methocarbamolMonitor Closely (1)methocarbamol and trifluoperazine both increase sedation. Use Caution/Monitor.methoxsalenMonitor Closely (1)methoxsalen, trifluoperazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.methscopolamineMonitor Closely (3)methscopolamine decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. methscopolamine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor. trifluoperazine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.methyl aminolevulinateSerious - Use Alternative (1)trifluoperazine, methyl aminolevulinate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.methyldopaSerious - Use Alternative (1)trifluoperazine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.methylenedioxymethamphetamineMonitor Closely (2)trifluoperazine, methylenedioxymethamphetamine. 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. trifluoperazine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methylergonovineMonitor Closely (1)methylergonovine, trifluoperazine. 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 (2)trifluoperazine, methylphenidate. 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. trifluoperazine 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)trifluoperazine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.metoclopramide intranasalSerious - Use Alternative (2)trifluoperazine, 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. trifluoperazine 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.metrizamideContraindicated (1)trifluoperazine, metrizamide. Mechanism: unknown. Contraindicated. Risk of seizure. D/C phenothiazine 24h before admin. of metrizamide.metyraponeMinor (1)trifluoperazine decreases effects