serotonin levels. Avoid or Use Alternate Drug.tretinoinperphenazine, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.tretinoin topicalperphenazine, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.trifluoperazineperphenazine and trifluoperazine both increase QTc interval. Avoid or Use Alternate Drug.trifluoperazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.trimipramineperphenazine 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.umeclidinium bromide/vilanterol inhaledamitriptyline 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 potentiatedamitriptyline 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.vandetanibamitriptyline, 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.venlafaxineperphenazine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.vemurafenibvemurafenib and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended.venlafaxinevenlafaxine and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug.vilanterol/fluticasone furoate inhaledamitriptyline and vilanterol/fluticasone furoate 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 potentiatedamitriptyline increases toxicity of vilanterol/fluticasone furoate 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 vilanterol/fluticasone furoate 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.vilazodoneamitriptyline, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .yohimbeyohimbe decreases effects of perphenazine by pharmacodynamic antagonism. Contraindicated.vortioxetineamitriptyline, vortioxetine. Either increases effects of the other by serotonin levels. Avoid or Use Alternate Drug.xylometazolineamitriptyline, xylometazoline. 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.yohimbeyohimbe, amitriptyline. Mechanism: unspecified interaction mechanism. Contraindicated. May cause increase or decrease in blood pressure.yohimbineamitriptyline, yohimbine. 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.ziprasidoneperphenazine and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.amitriptyline and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.Monitor Closely (526)5-HTPamitriptyline and 5-HTP both increase serotonin levels. Modify Therapy/Monitor Closely.abirateroneabiraterone increases levels of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.abiraterone increases levels of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.abobotulinumtoxinAabobotulinumtoxinA increases effects of amitriptyline by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects. .abobotulinumtoxinA increases effects of perphenazine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.aclidiniumaclidinium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.aclidinium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.perphenazine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.acrivastineacrivastine and perphenazine both increase sedation. Use Caution/Monitor.acrivastine and amitriptyline both increase sedation. Use Caution/Monitor.albiglutideperphenazine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.albuterolamitriptyline increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.albuterol and amitriptyline both increase QTc interval. Use Caution/Monitor.albuterolperphenazine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.alfentanilalfentanil and perphenazine both increase sedation. Use Caution/Monitor.alfentanil and amitriptyline both increase sedation. Use Caution/Monitor.alfuzosinalfuzosin and amitriptyline both increase QTc interval. Use Caution/Monitor.amitriptyline and alfuzosin both increase QTc interval. Use Caution/Monitor.alfuzosin and perphenazine both increase QTc interval. Use Caution/Monitor.perphenazine and alfuzosin both increase QTc interval. Use Caution/Monitor.almotriptanalmotriptan, 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).almotriptan and amitriptyline both increase serotonin levels. Modify Therapy/Monitor Closely.alprazolamalprazolam and perphenazine both increase sedation. Use Caution/Monitor.alprazolam and amitriptyline both increase sedation. Use Caution/Monitor.amifampridineamitriptyline increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.perphenazine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.amiodaroneamiodarone will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.amitriptylineperphenazine and amitriptyline both increase sedation. Use Caution/Monitor.amisulprideamitriptyline and amisulpride both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended if coadministered.amisulpride and amitriptyline both increase sedation. Use Caution/Monitor.amisulpride and amitriptyline both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended if coadministered.amobarbitalamobarbital and amitriptyline both increase sedation. Use Caution/Monitor.amobarbital will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.amobarbital will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.amobarbital and perphenazine both increase sedation. Use Caution/Monitor.amobarbital, amitriptyline. Other (see comment). Use Caution/Monitor. Comment: Barbiturates may increase adverse effects, including respiratory depression, produced by toxic doses of TCAs. With therapeutic doses of TCAs, barbiturates increase metabolism and decrease blood concentrations of TCAs.amoxapineamitriptyline and amoxapine both increase sedation. Use Caution/Monitor.perphenazine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.perphenazine and amoxapine both increase sedation. Use Caution/Monitor.amitriptyline and amoxapine both decrease cholinergic effects/transmission. Use Caution/Monitor.anagrelideanagrelide and perphenazine both increase QTc interval. Use Caution/Monitor.anticholinergic/sedative combosanticholinergic/sedative combos and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.anticholinergic/sedative combosanticholinergic/sedative combos decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.anticholinergic/sedative combos decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.perphenazine increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.apomorphineapomorphine and amitriptyline both increase QTc interval. Use Caution/Monitor.perphenazine and apomorphine both increase sedation. Use Caution/Monitor.amitriptyline and apomorphine both increase sedation. Use Caution/Monitor.aprepitantaprepitant will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.arformoterolperphenazine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.arformoterol and perphenazine both increase QTc interval. Use Caution/Monitor.arformoterolamitriptyline increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.arformoterol and amitriptyline both increase QTc interval. Use Caution/Monitor.aripiprazolearipiprazole and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.aripiprazole and amitriptyline both increase sedation. Use Caution/Monitor.aripiprazole and perphenazine both increase sedation. Use Caution/Monitor.aripiprazole and amitriptyline both increase QTc interval. Use Caution/Monitor.armodafinilperphenazine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.armodafinil will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.amitriptyline increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.artemetherartemether and perphenazine both increase QTc interval. Use Caution/Monitor.asenapineasenapine and amitriptyline both increase QTc interval. Use Caution/Monitor.asenapine and amitriptyline both increase sedation. Use Caution/Monitor.artemether/lumefantrineartemether/lumefantrine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.asenapineasenapine and perphenazine both increase QTc interval. Use Caution/Monitor.asenapine and perphenazine both increase sedation. Use Caution/Monitor.asenapine transdermalasenapine transdermal and amitriptyline both increase QTc interval. Use Caution/Monitor.asenapine transdermal and perphenazine both increase QTc interval. Use Caution/Monitor.asenapine transdermal and amitriptyline both increase sedation. Use Caution/Monitor.asenapine transdermal and perphenazine both increase sedation. Use Caution/Monitor.atazanaviratazanavir will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.atazanavir increases levels of amitriptyline by unspecified interaction mechanism. Use Caution/Monitor.atomoxetineperphenazine will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.atomoxetine and perphenazine both increase QTc interval. Use Caution/Monitor.atomoxetineatomoxetine and amitriptyline both increase QTc interval. Use Caution/Monitor.atorvastatinatorvastatin will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.atracuriumperphenazine increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.atracurium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.atracurium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.atracurium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.atropineatropine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.perphenazine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.atropine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.atropine and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.atropine IV/IMatropine IV/IM decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.perphenazine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.atropine IV/IM decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.atropine IV/IM and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.avapritinibavapritinib and amitriptyline both increase sedation. Use Caution/Monitor.avapritinib and perphenazine both increase sedation. Use Caution/Monitor.azelastineazelastine and amitriptyline both increase sedation. Use Caution/Monitor.azelastine and perphenazine both increase sedation. Use Caution/Monitor.azithromycinperphenazine and azithromycin both increase QTc interval. Use Caution/Monitor.amitriptyline and azithromycin both increase QTc interval. Use Caution/Monitor.baclofenbaclofen and perphenazine both increase sedation. Use Caution/Monitor.baclofen and amitriptyline both increase sedation. Use Caution/Monitor.bedaquilineamitriptyline and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closelyperphenazine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closelybelladonna alkaloidsperphenazine increases effects of belladonna alkaloids by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.belladonna alkaloids and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.belladonna alkaloids decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.belladonna alkaloids decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.belladonna and opiumbelladonna and opium and perphenazine both increase sedation. Use Caution/Monitor.belladonna and opium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.perphenazine increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.belladonna and opium and amitriptyline both increase sedation. Use Caution/Monitor.belladonna and opium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.belladonna and opium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.benperidolbenperidol and perphenazine both increase sedation. Use Caution/Monitor.benperidol and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.benperidol and amitriptyline both increase sedation. Use Caution/Monitor.benzhydrocodone/acetaminophenbenzhydrocodone/acetaminophen, amitriptyline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.benzhydrocodone/acetaminophen and perphenazine both increase sedation. Use Caution/Monitor.perphenazine will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the