toxicity of perphenazine by unspecified interaction mechanism. Minor/Significance Unknown.oxybutynin transdermalMonitor Closely (3)oxybutynin transdermal decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin transdermal decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin transdermal increases toxicity of perphenazine by unspecified interaction mechanism. Minor/Significance Unknown.oxycodoneMonitor Closely (2)perphenazine will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. oxycodone and perphenazine both increase sedation. Use Caution/Monitor.Minor (1)perphenazine decreases effects of oxycodone by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of oxycodone to active metabolite morphine.oxymorphoneMonitor Closely (2)perphenazine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. oxymorphone and perphenazine both increase sedation. Use Caution/Monitor.ozanimodMonitor Closely (1)ozanimod and perphenazine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.paliperidoneMonitor Closely (3)perphenazine and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely. paliperidone and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. paliperidone and perphenazine both increase sedation. Use Caution/Monitor.pancuroniumMonitor Closely (3)pancuronium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. pancuronium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.panobinostatMonitor Closely (1)panobinostat will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Panobinostat can increase the levels and effects of sensitive CYP2D6 substrates or those with a narrow therapeutic index CYP2D6.papaveretumMonitor Closely (1)papaveretum and perphenazine both increase sedation. Use Caution/Monitor.papaverineMonitor Closely (1)perphenazine and papaverine both increase sedation. Use Caution/Monitor.parecoxibMinor (1)parecoxib will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.paroxetineMonitor Closely (1)paroxetine, 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 (3)perphenazine and paroxetine both increase QTc interval. Avoid or Use Alternate Drug. paroxetine 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 paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.pasireotideMonitor Closely (1)perphenazine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.pazopanibMonitor Closely (1)perphenazine and pazopanib both increase QTc interval. Use Caution/Monitor.peginterferon alfa 2bMonitor Closely (1)peginterferon alfa 2b, perphenazine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.pentamidineContraindicated (1)perphenazine and pentamidine both increase QTc interval. Contraindicated.pentazocineMonitor Closely (1)pentazocine and perphenazine both increase sedation. Use Caution/Monitor.pentobarbitalMonitor Closely (1)pentobarbital and perphenazine both increase sedation. Use Caution/Monitor.perhexilineMinor (1)perphenazine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.perindoprilMinor (1)perphenazine increases effects of perindopril by unspecified interaction mechanism. Minor/Significance Unknown.phendimetrazineMonitor Closely (2)perphenazine, phendimetrazine. 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 phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenelzineMonitor Closely (1)phenelzine, 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).phenobarbitalMonitor Closely (1)phenobarbital and perphenazine both increase sedation. Use Caution/Monitor.phentermineMonitor Closely (2)perphenazine, phentermine. 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 phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrineMonitor Closely (2)perphenazine, phenylephrine. 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 phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrine POMonitor Closely (2)perphenazine, phenylephrine PO. 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 phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .pholcodineMonitor Closely (1)perphenazine and pholcodine both increase sedation. Use Caution/Monitor.pimozideContraindicated (1)perphenazine and pimozide both increase QTc interval. Contraindicated.Monitor Closely (2)perphenazine and pimozide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and pimozide both increase sedation. Use Caution/Monitor.pirbuterolMonitor Closely (1)perphenazine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.porfimerMonitor Closely (1)perphenazine, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.posaconazoleMonitor Closely (1)perphenazine and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.pralidoximeMonitor Closely (3)pralidoxime decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. pralidoxime decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.pramipexoleSerious - Use Alternative (1)perphenazine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.primaquineMonitor Closely (1)primaquine and perphenazine both increase QTc interval. Use Caution/Monitor.primidoneMonitor Closely (1)primidone and perphenazine both increase sedation. Use Caution/Monitor.procainamideContraindicated (1)perphenazine and procainamide both increase QTc interval. Contraindicated.procarbazineMonitor Closely (2)procarbazine, 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). procarbazine, perphenazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Excessive sedation.prochlorperazineMonitor Closely (2)perphenazine and prochlorperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and prochlorperazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and prochlorperazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)perphenazine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.promazineSerious - Use Alternative (1)perphenazine and promazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)perphenazine will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.promethazineMonitor Closely (3)promethazine, 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). perphenazine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. promethazine and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)perphenazine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.propafenoneMonitor Closely (2)perphenazine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. propafenone will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.propanthelineMonitor Closely (3)propantheline decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. propantheline decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.propofolMonitor Closely (1)propofol and perphenazine both increase sedation. Use Caution/Monitor.propranololMonitor Closely (1)perphenazine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.propylhexedrineMonitor Closely (2)perphenazine, propylhexedrine. 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 propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.protriptylineMonitor Closely (1)perphenazine and protriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and protriptyline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)protriptyline, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. protriptyline, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.pseudoephedrineMonitor Closely (1)perphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.pyrimethamineMinor (1)pyrimethamine increases levels of perphenazine by decreasing metabolism. Minor/Significance Unknown.quazepamMonitor Closely (1)quazepam and perphenazine both increase sedation. Use Caution/Monitor.quetiapineMonitor Closely (2)perphenazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and quetiapine both increase sedation. Use Caution/Monitor.quinacrineMinor (1)quinacrine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.quinaprilMinor (1)perphenazine increases effects of quinapril by unspecified interaction mechanism. Minor/Significance Unknown.quinidineContraindicated (1)perphenazine and quinidine both increase QTc interval. Contraindicated.Monitor Closely (1)quinidine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)quinidine, perphenazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.quinineMonitor Closely (1)perphenazine and quinine both increase QTc interval. Use Caution/Monitor.ramelteonMonitor Closely (1)perphenazine and ramelteon both increase sedation. Use Caution/Monitor.ramiprilMinor (1)perphenazine increases effects of ramipril by unspecified interaction mechanism. Minor/Significance Unknown.ranolazineMonitor Closely (1)perphenazine and ranolazine both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)ranolazine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.rapacuroniumMonitor Closely (3)rapacuronium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. rapacuronium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.remimazolamMonitor Closely (1)remimazolam, perphenazine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.ribociclibSerious - Use Alternative (1)ribociclib increases toxicity of perphenazine by QTc interval. Avoid or Use Alternate Drug.rimabotulinumtoxinBMonitor Closely (1)perphenazine, rimabotulinumtoxinB. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.risperidoneMonitor Closely (3)perphenazine and risperidone both increase QTc interval. Modify Therapy/Monitor Closely. perphenazine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and risperidone both increase sedation. Use Caution/Monitor.Minor (1)perphenazine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.ritonavirMinor (1)ritonavir will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.rizatriptanMonitor Closely (1)rizatriptan, 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).rocuroniumMonitor Closely (3)rocuronium decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. rocuronium decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor. perphenazine increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.rolapitantMonitor Closely (1)rolapitant will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.romidepsinMonitor Closely (1)perphenazine and romidepsin both increase QTc interval. Modify Therapy/Monitor Closely.ropiniroleSerious - Use Alternative (1)perphenazine decreases effects of ropinirole by pharmacodynamic antagonism.