Drug.brompheniramineMonitor Closely (2)brompheniramine and amitriptyline both increase sedation. Use Caution/Monitor. brompheniramine and perphenazine both increase sedation. Use Caution/Monitor.budesonideMinor (1)budesonide will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.buprenorphineMonitor Closely (3)buprenorphine and perphenazine both increase QTc interval. Use Caution/Monitor. buprenorphine and amitriptyline both increase sedation. Use Caution/Monitor. buprenorphine and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)buprenorphine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.buprenorphine buccalMonitor Closely (3)buprenorphine buccal and amitriptyline both increase sedation. Use Caution/Monitor. buprenorphine buccal and perphenazine both increase QTc interval. Use Caution/Monitor. buprenorphine buccal and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)buprenorphine buccal and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.buprenorphine subdermal implantMonitor Closely (3)buprenorphine subdermal implant and perphenazine both increase QTc interval. Use Caution/Monitor. amitriptyline, buprenorphine subdermal implant. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected. buprenorphine subdermal implant and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)buprenorphine subdermal implant and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. buprenorphine subdermal implant and amitriptyline both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebuprenorphine transdermalMonitor Closely (2)buprenorphine transdermal and perphenazine both increase sedation. Use Caution/Monitor. buprenorphine transdermal and perphenazine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (2)buprenorphine transdermal and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. buprenorphine transdermal and amitriptyline both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebuprenorphine, long-acting injectionMonitor Closely (4)buprenorphine, long-acting injection and perphenazine both increase sedation. Use Caution/Monitor. perphenazine increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate. buprenorphine, long-acting injection and perphenazine both increase QTc interval. Use Caution/Monitor. amitriptyline, buprenorphine, long-acting injection. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.Serious - Use Alternative (2)buprenorphine, long-acting injection and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. buprenorphine, long-acting injection and amitriptyline both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebupropionMonitor Closely (4)bupropion will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. bupropion will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. perphenazine increases toxicity of bupropion by unspecified interaction mechanism. Use Caution/Monitor. May lower seizure threshold; keep bupropion dose as low as possible. amitriptyline increases toxicity of bupropion by unspecified interaction mechanism. Use Caution/Monitor. May lower seizure threshold; keep bupropion dose as low as possible.buspironeSerious - Use Alternative (1)amitriptyline and buspirone both increase serotonin levels. Avoid or Use Alternate Drug.butabarbitalMonitor Closely (4)butabarbital and perphenazine both increase sedation. Use Caution/Monitor. butabarbital will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. butabarbital will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. butabarbital and amitriptyline both increase sedation. Use Caution/Monitor.Minor (1)butabarbital, amitriptyline. Other (see comment). Minor/Significance Unknown. 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.butalbitalMonitor Closely (4)butalbital will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. butalbital will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. butalbital and perphenazine both increase sedation. Use Caution/Monitor. butalbital and amitriptyline both increase sedation. Use Caution/Monitor.Minor (1)butalbital, amitriptyline. Other (see comment). Minor/Significance Unknown. 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.butorphanolMonitor Closely (2)butorphanol and perphenazine both increase sedation. Use Caution/Monitor. butorphanol and amitriptyline both increase sedation. Use Caution/Monitor.cabergolineSerious - Use Alternative (1)perphenazine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.caffeineMonitor Closely (2)perphenazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. amitriptyline increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.calcium/magnesium/potassium/sodium oxybatesSerious - Use Alternative (2)perphenazine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation. amitriptyline, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.captoprilMinor (1)perphenazine increases effects of captopril by unspecified interaction mechanism. Minor/Significance Unknown.carbacholMonitor Closely (1)carbachol increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.carbamazepineMonitor Closely (1)carbamazepine will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)carbamazepine decreases levels of amitriptyline by increasing metabolism. Minor/Significance Unknown.carbinoxamineMonitor Closely (2)carbinoxamine and amitriptyline both increase sedation. Use Caution/Monitor. carbinoxamine and perphenazine both increase sedation. Use Caution/Monitor.carisoprodolMonitor Closely (2)carisoprodol and amitriptyline both increase sedation. Use Caution/Monitor. carisoprodol and perphenazine both increase sedation. Use Caution/Monitor.carvedilolMonitor Closely (1)perphenazine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.celecoxibMinor (1)celecoxib will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cenobamateMonitor Closely (2)cenobamate, amitriptyline. Either increases effects of the other by sedation. Use Caution/Monitor. cenobamate, perphenazine. Either increases effects of the other by sedation. Use Caution/Monitor.ceritinibMonitor Closely (2)ceritinib and perphenazine both increase QTc interval. Use Caution/Monitor. ceritinib and amitriptyline both increase QTc interval. Use Caution/Monitor.cevimelineMonitor Closely (1)cevimeline increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.chasteberryMinor (1)chasteberry decreases effects of perphenazine by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).chloral hydrateMonitor Closely (2)chloral hydrate and perphenazine both increase sedation. Use Caution/Monitor. chloral hydrate and amitriptyline both increase sedation. Use Caution/Monitor.chlordiazepoxideMonitor Closely (2)chlordiazepoxide and perphenazine both increase sedation. Use Caution/Monitor. chlordiazepoxide and amitriptyline both increase sedation. Use Caution/Monitor.chloroquineMonitor Closely (1)chloroquine increases toxicity of amitriptyline by QTc interval. Use Caution/Monitor.Minor (3)chloroquine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown. chloroquine increases levels of perphenazine by decreasing metabolism. Minor/Significance Unknown. chloroquine increases toxicity of perphenazine by QTc interval. Minor/Significance Unknown.chlorpheniramineMonitor Closely (2)chlorpheniramine and amitriptyline both increase sedation. Use Caution/Monitor. chlorpheniramine and perphenazine both increase sedation. Use Caution/Monitor.chlorpromazineMonitor Closely (3)chlorpromazine and perphenazine both increase sedation. Use Caution/Monitor. chlorpromazine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. chlorpromazine and amitriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)chlorpromazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. chlorpromazine and perphenazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (3)amitriptyline, chlorpromazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. amitriptyline, chlorpromazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects. perphenazine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.chlorpropamideMinor (1)amitriptyline increases effects of chlorpropamide by pharmacodynamic synergism. Minor/Significance Unknown.chlorzoxazoneMonitor Closely (2)chlorzoxazone and perphenazine both increase sedation. Use Caution/Monitor. chlorzoxazone and amitriptyline both increase sedation. Use Caution/Monitor.cigarette smokingMonitor Closely (1)cigarette smoking decreases levels of perphenazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.cimetidineMonitor Closely (1)cimetidine will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)cimetidine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.cinnarizineMonitor Closely (2)cinnarizine and amitriptyline both increase sedation. Use Caution/Monitor. cinnarizine and perphenazine both increase sedation. Use Caution/Monitor.cisatracuriumMonitor Closely (4)cisatracurium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. cisatracurium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. cisatracurium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.citalopramMonitor Closely (1)citalopram and perphenazine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (2)citalopram and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug. citalopram and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug. Citalopram may increase TCA levels. Increased risk of serotonin syndrome or neuroleptic malignant syndrome. Potential risk for QT prolongation. ECG monitoring is recommended.clarithromycinMonitor Closely (1)clarithromycin will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (3)clarithromycin will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. perphenazine and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug. amitriptyline and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.clemastineMonitor Closely (2)clemastine and amitriptyline both increase sedation. Use Caution/Monitor. clemastine and perphenazine both increase sedation. Use Caution/Monitor.clobazamMonitor Closely (3)amitriptyline, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression). clobazam will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly. clobazam will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly. clomipramineMonitor Closely (4)amitriptyline and clomipramine both increase sedation. Use Caution/Monitor. perphenazine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. amitriptyline and clomipramine both decrease cholinergic effects/transmission. Use Caution/Monitor. perphenazine and clomipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (3)perphenazine and clomipramine both increase QTc interval. Avoid or Use Alternate Drug. amitriptyline and clomipramine both increase serotonin levels. Avoid or Use Alternate Drug. amitriptyline and clomipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)clomipramine, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. clomipramine, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.clonazepamMonitor Closely (2)clonazepam and perphenazine both increase sedation. Use Caution/Monitor. clonazepam and amitriptyline both increase sedation. Use Caution/Monitor.clonidineMonitor Closely (1)clonidine, perphenazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.Serious - Use Alternative (1)amitriptyline decreases effects of clonidine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.clorazepateMonitor Closely (2)clorazepate and perphenazine both increase sedation. Use Caution/Monitor. clorazepate and amitriptyline both increase sedation. Use Caution/Monitor.clotrimazoleMonitor Closely (1)clotrimazole will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.clozapineMonitor Closely (5)clozapine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. clozapine and amitriptyline both increase sedation. Use Caution/Monitor. clozapine and amitriptyline both increase QTc interval. Use Caution/Monitor. clozapine and perphenazine both increase QTc interval. Use Caution/Monitor. clozapine and perphenazine both increase sedation. Use Caution/Monitor.cobicistatMonitor Closely (3)cobicistat will increase the level or effect of perphenazine by Other (see comment). Modify Therapy/Monitor Closely. A decrease in the dose of antipsychotics that are metabolized by CYP3A or CYP2D6 may be needed upon coadministration. cobicistat will increase the level