necessarytacrolimusMonitor Closely (2)tacrolimus and perphenazine both increase QTc interval. Use Caution/Monitor. tacrolimus will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.tamoxifenMonitor Closely (1)perphenazine decreases effects of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.tapentadolMonitor Closely (3)tapentadol and perphenazine both increase sedation. Use Caution/Monitor. amitriptyline and tapentadol both increase serotonin levels. Modify Therapy/Monitor Closely. tapentadol and amitriptyline both increase sedation. Use Caution/Monitor.tedizolidSerious - Use Alternative (1)tedizolid, amitriptyline. Either increases effects of the other by Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. both increase serotonin levels; increased risk of serotonin syndrome.telavancinMonitor Closely (2)perphenazine and telavancin both increase QTc interval. Modify Therapy/Monitor Closely. amitriptyline and telavancin both increase QTc interval. Modify Therapy/Monitor Closely.temazepamMonitor Closely (2)temazepam and amitriptyline both increase sedation. Use Caution/Monitor. temazepam and perphenazine both increase sedation. Use Caution/Monitor.terbinafineMonitor Closely (2)terbinafine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug. terbinafine will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.terbutalineMonitor Closely (2)perphenazine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. amitriptyline increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)amitriptyline, terbutaline. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.teriflunomideMonitor Closely (1)teriflunomide decreases levels of amitriptyline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.tetrabenazineMonitor Closely (2)perphenazine and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely. tetrabenazine and amitriptyline both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)tetrabenazine and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.thioridazineMonitor Closely (3)perphenazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. thioridazine and amitriptyline both increase sedation. Use Caution/Monitor. perphenazine and thioridazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (3)perphenazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug. thioridazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. perphenazine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.Minor (3)amitriptyline, thioridazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. amitriptyline, thioridazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects. thioridazine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.thiothixeneMonitor Closely (3)perphenazine and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and thiothixene both increase sedation. Use Caution/Monitor. thiothixene and amitriptyline both increase sedation. Use Caution/Monitor.thyroid desiccatedMonitor Closely (1)thyroid desiccated increases effects of amitriptyline by Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.timololMonitor Closely (1)perphenazine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.tiotropiumMonitor Closely (4)tiotropium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor. tiotropium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. tiotropium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. perphenazine increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.tipranavirMinor (1)tipranavir will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.tobacco useMonitor Closely (1)tobacco use decreases levels of perphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.tolazamideMinor (1)amitriptyline increases effects of tolazamide by pharmacodynamic synergism. Minor/Significance Unknown.tolbutamideMinor (1)amitriptyline increases effects of tolbutamide by pharmacodynamic synergism. Minor/Significance Unknown.tolterodineMonitor Closely (4)tolterodine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. tolterodine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. tolterodine and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.Minor (1)perphenazine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.tolvaptanMonitor Closely (1)tolvaptan will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.topiramateMonitor Closely (3)amitriptyline and topiramate both increase sedation. Modify Therapy/Monitor Closely. perphenazine and topiramate both increase sedation. Modify Therapy/Monitor Closely. topiramate increases toxicity of amitriptyline by unspecified interaction mechanism. Use Caution/Monitor. Amitriptyline levels may increase; adjust dose based on clinical response and not on basis of plasma levels.toremifeneSerious - Use Alternative (1)amitriptyline and toremifene both increase QTc interval. Avoid or Use Alternate Drug. Concurrent use of toremifene with agents causing QT prolongation should be avoided. If concomitant use is required it's recommended that toremifene be interrupted. If interruption not possible, patients requiring therapy with a drug that prolongs QT should be closely monitored. ECGs should be obtained for high risk patients.tramadolMonitor Closely (3)tramadol and perphenazine both increase sedation. Use Caution/Monitor. amitriptyline and tramadol both increase serotonin levels. Modify Therapy/Monitor Closely. tramadol and amitriptyline both increase sedation. Use Caution/Monitor.trandolaprilMinor (1)perphenazine increases effects of trandolapril by unspecified interaction mechanism. Minor/Significance Unknown.tranylcypromineContraindicated (1)tranylcypromine and amitriptyline both increase serotonin levels. Contraindicated.Monitor Closely (1)tranylcypromine, 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).trazodoneMonitor Closely (4)amitriptyline and trazodone both decrease cholinergic effects/transmission. Use Caution/Monitor. trazodone will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. perphenazine and trazodone both increase sedation. Use Caution/Monitor. amitriptyline and trazodone both increase sedation. Use Caution/Monitor.Serious - Use Alternative (3)perphenazine and trazodone both increase QTc interval. Avoid or Use Alternate Drug. amitriptyline and trazodone both increase QTc interval. Avoid or Use Alternate Drug. trazodone and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug.Minor (2)trazodone, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. trazodone, perphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.tretinoinSerious - Use Alternative (1)perphenazine, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.tretinoin topicalSerious - Use Alternative (1)perphenazine, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.triazolamMonitor Closely (2)triazolam and perphenazine both increase sedation. Use Caution/Monitor. triazolam and amitriptyline both increase sedation. Use Caution/Monitor.triclofosMonitor Closely (2)triclofos and perphenazine both increase sedation. Use Caution/Monitor. triclofos and amitriptyline both increase sedation. Use Caution/Monitor.trifluoperazineMonitor Closely (3)perphenazine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and trifluoperazine both increase sedation. Use Caution/Monitor. trifluoperazine and amitriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)perphenazine and trifluoperazine both increase QTc interval. Avoid or Use Alternate Drug. trifluoperazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.Minor (3)perphenazine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown. amitriptyline, trifluoperazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. amitriptyline, trifluoperazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.trihexyphenidylMonitor Closely (3)trihexyphenidyl decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. trihexyphenidyl and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor. Potential for additive anticholinergic effects. perphenazine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.trimethoprimMonitor Closely (2)perphenazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely. amitriptyline and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.trimipramineMonitor Closely (3)perphenazine and trimipramine both increase sedation. Use Caution/Monitor. amitriptyline and trimipramine both decrease cholinergic effects/transmission. Use Caution/Monitor. amitriptyline and trimipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (3)perphenazine and trimipramine both increase QTc interval. Avoid or Use Alternate Drug. amitriptyline and trimipramine both increase QTc interval. Avoid or Use Alternate Drug. amitriptyline and trimipramine both increase serotonin levels. Avoid or Use Alternate Drug.Minor (2)trimipramine, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. trimipramine, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.triprolidineMonitor Closely (2)triprolidine and perphenazine both increase sedation. Use Caution/Monitor. triprolidine and amitriptyline both increase sedation. Use Caution/Monitor.tropisetronMonitor Closely (2)perphenazine and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely. amitriptyline and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)perphenazine will increase the level or effect of tropisetron by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.trospium chlorideMonitor Closely (4)trospium chloride decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. trospium chloride and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor. perphenazine increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. trospium chloride decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.tucatinibMonitor Closely (1)tucatinib will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.umeclidinium bromide/vilanterol inhaledSerious - Use Alternative (3)amitriptyline and umeclidinium bromide/vilanterol inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Exercise extreme caution if vilanterol coadministered with MAOIs or TCAs, or within 2 weeks of discontinuation of these drugs; adrenergic agonist effects on the cardiovascular system may be potentiated amitriptyline increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated. perphenazine increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.valbenazineMonitor Closely (2)valbenazine and amitriptyline both increase QTc interval. Use Caution/Monitor. valbenazine and perphenazine both increase QTc interval. Use Caution/Monitor.valerianMonitor Closely (1)valerian and amitriptyline both increase sedation. Use Caution/Monitor.vandetanibSerious - Use Alternative (1)amitriptyline, vandetanib. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. Avoid coadministration with drugs known to prolong QT interval; if a drug known to prolong QT interval must be used, more frequent ECG monitoring is recommended.vasopressinMinor (1)amitriptyline increases effects of vasopressin by pharmacodynamic synergism. Minor/Significance Unknown.vecuroniumMonitor Closely (4)vecuronium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. vecuronium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. vecuronium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.vemurafenibSerious - Use Alternative (1)vemurafenib and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended.venlafaxineMonitor Closely (3)venlafaxine, 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). amitriptyline and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely. venlafaxine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)venlafaxine and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug. perphenazine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.verapamilMonitor Closely (1)verapamil will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. The frequency and severity of amitriptyline adverse effects (sedation, anticholinergic effects and orthostatic hypotension) may be increased. Cardiac dysrhythmic effects may be additive. Minor (2)verapamil will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. verapamil increases levels of amitriptyline by decreasing metabolism. Minor/Significance Unknown.vilanterol/fluticasone furoate inhaledSerious - Use Alternative (3)amitriptyline and vilanterol/fluticasone furoate inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or