with other drugs that prolong QTc interval, presence of congenital QT prolongation).deutetrabenazineperphenazine and deutetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely. The risk for parkinsonism, neuroleptic malignant syndrome, and akathisia may be increased by concomitant use of deutetrabenazine and dopamine antagonists or antipsychotics.perphenazine and deutetrabenazine both increase sedation. Use Caution/Monitor.deutetrabenazine and perphenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).dexchlorpheniraminedexchlorpheniramine and amitriptyline both increase sedation. Use Caution/Monitor.dexchlorpheniramine and perphenazine both increase sedation. Use Caution/Monitor.dexfenfluramineperphenazine, dexfenfluramine. 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.amitriptyline and dexfenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.perphenazine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexmedetomidinedexmedetomidine and perphenazine both increase sedation. Use Caution/Monitor.dexmedetomidine and amitriptyline both increase sedation. Use Caution/Monitor.dexmethylphenidateperphenazine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.perphenazine, dexmethylphenidate. 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.dextroamphetamineamitriptyline increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline and dextroamphetamine both increase serotonin levels. Modify Therapy/Monitor Closely.perphenazine, dextroamphetamine. 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.amitriptyline increases effects of dextroamphetamine by unknown mechanism. Use Caution/Monitor.perphenazine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dextroamphetamine transdermalamitriptyline will increase the level or effect of dextroamphetamine transdermal by pharmacodynamic synergism. Modify Therapy/Monitor Closely. May enhance the activity of tricyclic or sympathomimetic agents causing striking and sustained increases in dextroamphetamine levels in brain; May be potentiate cardiovascular effects. Monitor frequently and adjust or use an alternant based on clinical response.perphenazine, dextroamphetamine transdermal. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and concomitant serotonergic drug(s).dextromethorphandextromethorphan, 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).dextromoramidedextromoramide and amitriptyline both increase sedation. Use Caution/Monitor.dextromoramidedextromoramide and perphenazine both increase sedation. Use Caution/Monitor.diamorphinediamorphine and perphenazine both increase sedation. Use Caution/Monitor.diamorphine and amitriptyline both increase sedation. Use Caution/Monitor.diazepamdiazepam and perphenazine both increase sedation. Use Caution/Monitor.diazepam and amitriptyline both increase sedation. Use Caution/Monitor.diazepam intranasaldiazepam intranasal, amitriptyline. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.dicyclominedicyclomine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.dicyclomine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.perphenazine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.dicyclominedicyclomine and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.diethylpropionperphenazine, diethylpropion. 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 diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.difelikefalindifelikefalin and perphenazine both increase sedation. Use Caution/Monitor.difelikefalin and amitriptyline both increase sedation. Use Caution/Monitor.difenoxin hcldifenoxin hcl and perphenazine both increase sedation. Use Caution/Monitor.difenoxin hcl and amitriptyline both increase sedation. Use Caution/Monitor.dihydroergotaminedihydroergotamine, 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 dihydroergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.dihydroergotamine intranasalamitriptyline and dihydroergotamine intranasal both increase serotonin levels. Modify Therapy/Monitor Closely.dimenhydrinatedimenhydrinate and perphenazine both increase sedation. Use Caution/Monitor.diltiazemdiltiazem will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use with amitriptyline may alter blood pressure control.dimenhydrinatedimenhydrinate and amitriptyline both increase sedation. Use Caution/Monitor.diphenhydramineperphenazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.diphenhydramine and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.diphenhydramine and amitriptyline both increase sedation. Use Caution/Monitor.diphenhydramine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.diphenhydramine and perphenazine both increase sedation. Use Caution/Monitor.diphenhydramine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.diphenoxylate hcldiphenoxylate hcl and perphenazine both increase sedation. Use Caution/Monitor.diphenoxylate hcl and amitriptyline both increase sedation. Use Caution/Monitor.dipipanonedipipanone and perphenazine both increase sedation. Use Caution/Monitor.dipipanone and amitriptyline both increase sedation. Use Caution/Monitor.dobutamineperphenazine, dobutamine. 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 dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dofetilidedofetilide increases toxicity of perphenazine by QTc interval. Use Caution/Monitor.dofetilide increases toxicity of amitriptyline by QTc interval. Use Caution/Monitor.dolasetronperphenazine and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.amitriptyline and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.donepezildonepezil and amitriptyline both increase QTc interval. Use Caution/Monitor.donepezil increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.donepezil and perphenazine both increase QTc interval. Use Caution/Monitor.donepezil transdermaldonepezil transdermal, perphenazine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.dopamineamitriptyline increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dopamineperphenazine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.perphenazine, dopamine. 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.dopexamineperphenazine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dosulepinamitriptyline and dosulepin both decrease cholinergic effects/transmission. Use Caution/Monitor.perphenazine and dosulepin both increase sedation. Use Caution/Monitor.amitriptyline and dosulepin both increase sedation. Use Caution/Monitor.doxepinperphenazine and doxepin both increase sedation. Use Caution/Monitor.amitriptyline and doxepin both decrease cholinergic effects/transmission. Use Caution/Monitor.amitriptyline and doxepin both increase sedation. Use Caution/Monitor.doxylaminedoxylamine and amitriptyline both increase sedation. Use Caution/Monitor.doxylamine and perphenazine both increase sedation. Use Caution/Monitor.droperidoldroperidol and perphenazine both increase sedation. Use Caution/Monitor.droperidol and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.droperidol and amitriptyline both increase sedation. Use Caution/Monitor.duloxetineperphenazine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.echothiophate iodideechothiophate iodide increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.efavirenzefavirenz and amitriptyline both increase QTc interval. Use Caution/Monitor.efavirenz and perphenazine both increase QTc interval. Use Caution/Monitor.efavirenz will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.efavirenz will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.elagolixelagolix will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.eletriptaneletriptan, 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).eletriptaneletriptan and amitriptyline both increase serotonin levels. Modify Therapy/Monitor Closely.eliglustateliglustat and perphenazine both increase QTc interval. Use Caution/Monitor.eliglustat and amitriptyline both increase QTc interval. Use Caution/Monitor.eliglustat increases levels of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.eliglustat increases levels of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.eliglustat increases levels of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.elvitegravir/cobicistat/emtricitabine/tenofovir DFelvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; A decrease in dose of the neuroleptic may be needed when coadministered.elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.encorafenibencorafenib and perphenazine both increase QTc interval. Use Caution/Monitor.entrectinibentrectinib and amitriptyline both increase QTc interval. Use Caution/Monitor.entrectinibentrectinib and perphenazine both increase QTc interval. Use Caution/Monitor.ephedrineperphenazine, ephedrine. 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 ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases effects of ephedrine by unknown mechanism. Use Caution/Monitor.amitriptyline increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrineamitriptyline increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases effects of epinephrine by unknown mechanism. Use Caution/Monitor.perphenazine decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.perphenazine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.perphenazine, epinephrine. 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.epinephrine inhaledamitriptyline and epinephrine inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Tricyclic antidepressants may potentiate epinephrine effect on cardiovascular system.epinephrine racemicperphenazine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.perphenazine decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.epinephrine racemicamitriptyline increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline increases effects of epinephrine racemic by unknown mechanism. Use Caution/Monitor.ergoloid mesylatesergoloid mesylates, 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).ergotamineergotamine, 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 ergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.eribulineribulin and amitriptyline both increase QTc interval. Use Caution/Monitor.eribulin and perphenazine both increase QTc interval. Use Caution/Monitor.escitalopramescitalopram increases toxicity of perphenazine by QTc interval. Use Caution/Monitor.esketamine intranasalesketamine intranasal, amitriptyline. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.eslicarbazepine acetateeslicarbazepine acetate will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.esomeprazoleesomeprazole will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.estazolamestazolam and amitriptyline