hcl and perphenazine both increase sedation. Use Caution/Monitor.dihydroergotamineMonitor Closely (1)dihydroergotamine, 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).dimenhydrinateMonitor Closely (1)dimenhydrinate and perphenazine both increase sedation. Use Caution/Monitor.diphenhydramineMonitor Closely (4)diphenhydramine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. diphenhydramine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. diphenhydramine and perphenazine both increase sedation. Use Caution/Monitor.Minor (1)diphenhydramine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.diphenoxylate hclMonitor Closely (1)diphenoxylate hcl and perphenazine both increase sedation. Use Caution/Monitor.dipipanoneMonitor Closely (1)dipipanone and perphenazine both increase sedation. Use Caution/Monitor.disopyramideContraindicated (1)perphenazine and disopyramide both increase QTc interval. Contraindicated.dobutamineMonitor Closely (2)perphenazine, 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.dofetilideMonitor Closely (1)dofetilide increases toxicity of perphenazine by QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.dolasetronMonitor Closely (1)perphenazine and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.donepezilMonitor Closely (1)donepezil and perphenazine both increase QTc interval. Use Caution/Monitor.Minor (1)perphenazine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.donepezil transdermalMonitor Closely (1)donepezil transdermal, perphenazine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.dopamineMonitor Closely (2)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. perphenazine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.dopexamineMonitor Closely (1)perphenazine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dosulepinMonitor Closely (1)perphenazine and dosulepin both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and dosulepin both increase QTc interval. Avoid or Use Alternate Drug.doxepinMonitor Closely (1)perphenazine and doxepin both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and doxepin both increase QTc interval. Avoid or Use Alternate Drug.Minor (3)perphenazine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown. doxepin, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. doxepin, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.doxylamineMonitor Closely (1)doxylamine and perphenazine both increase sedation. Use Caution/Monitor.dronedaroneSerious - Use Alternative (1)perphenazine and dronedarone both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)dronedarone will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.droperidolMonitor Closely (2)droperidol and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. droperidol and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and droperidol both increase QTc interval. Avoid or Use Alternate Drug.duloxetineMonitor Closely (1)perphenazine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Minor (1)duloxetine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.efavirenzMonitor Closely (1)efavirenz and perphenazine both increase QTc interval. Use Caution/Monitor.eletriptanMonitor Closely (1)eletriptan, 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).eliglustatMonitor Closely (2)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. eliglustat and perphenazine both increase QTc interval. Use Caution/Monitor.elvitegravir/cobicistat/emtricitabine/tenofovir DFMonitor Closely (1)elvitegravir/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.enalaprilMinor (1)perphenazine increases effects of enalapril by unspecified interaction mechanism. Minor/Significance Unknown.encainideMinor (1)perphenazine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.encorafenibMonitor Closely (1)encorafenib and perphenazine both increase QTc interval. Use Caution/Monitor.entrectinibMonitor Closely (1)entrectinib and perphenazine both increase QTc interval. Use Caution/Monitor.ephedrineMonitor Closely (2)perphenazine, 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.epinephrineMonitor Closely (3)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. 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.Serious - Use Alternative (1)epinephrine and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.epinephrine racemicMonitor Closely (2)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. perphenazine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)epinephrine racemic and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.ergoloid mesylatesMonitor Closely (1)ergoloid 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).ergotamineMonitor Closely (1)ergotamine, 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).eribulinMonitor Closely (1)eribulin and perphenazine both increase QTc interval. Use Caution/Monitor.erythromycin baseSerious - Use Alternative (1)perphenazine and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.erythromycin ethylsuccinateSerious - Use Alternative (1)perphenazine and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.erythromycin lactobionateSerious - Use Alternative (1)perphenazine and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.erythromycin stearateSerious - Use Alternative (1)perphenazine and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.escitalopramMonitor Closely (1)escitalopram increases toxicity of perphenazine by QTc interval. Use Caution/Monitor.estazolamMonitor Closely (1)estazolam and perphenazine both increase sedation. Use Caution/Monitor.ethanolMonitor Closely (1)perphenazine and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol, perphenazine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.etomidateMonitor Closely (1)etomidate and perphenazine both increase sedation. Use Caution/Monitor.eucalyptusMinor (1)perphenazine and eucalyptus both increase sedation. Minor/Significance Unknown.fedratinibMonitor Closely (1)fedratinib will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.fenfluramineMonitor Closely (2)perphenazine, fenfluramine. 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 fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fentanylMonitor Closely (1)fentanyl, 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)fentanyl, perphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.fentanyl intranasalSerious - Use Alternative (1)fentanyl intranasal, perphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.fentanyl transdermalSerious - Use Alternative (1)fentanyl transdermal, perphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.fentanyl transmucosalSerious - Use Alternative (1)fentanyl transmucosal, perphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.fesoterodineMonitor Closely (3)fesoterodine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)perphenazine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.fezolinetantContraindicated (1)perphenazine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitorsfingolimodMonitor Closely (1)fingolimod and perphenazine both increase QTc interval. Use Caution/Monitor.flavoxateMonitor Closely (3)flavoxate decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. flavoxate decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.flecainideMonitor Closely (2)perphenazine will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. perphenazine and flecainide both increase QTc interval. Modify Therapy/Monitor Closely.flibanserinMonitor Closely (1)flibanserin, perphenazine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. 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).fluconazoleSerious - Use Alternative (1)perphenazine and fluconazole both increase QTc interval. Avoid or Use Alternate Drug.fluoxetineSerious - Use Alternative (3)perphenazine and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. fluoxetine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. perphenazine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.fluphenazineMonitor Closely (2)fluphenazine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. fluphenazine and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)fluphenazine and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)perphenazine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.flurazepamMonitor Closely (1)flurazepam and perphenazine both increase sedation. Use Caution/Monitor.fluvoxamineMonitor Closely (1)fluvoxamine and perphenazine both increase QTc interval. Use Caution/Monitor.formoterolMonitor Closely (1)perphenazine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.foscarnetMonitor Closely (1)perphenazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.fosinoprilMinor (1)perphenazine