absorption. Applies only to oral form of both agents. Use Caution/Monitor.meclizine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.melatonintrifluoperazine and melatonin both increase sedation. Use Caution/Monitor.meperidinemeperidine and trifluoperazine both increase sedation. Use Caution/Monitor.meperidine, trifluoperazine. 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).meprobamatetrifluoperazine and meprobamate both increase sedation. Use Caution/Monitor.metaproterenoltrifluoperazine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaxalonemetaxalone and trifluoperazine both increase sedation. Use Caution/Monitor.metformintrifluoperazine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.methadonetrifluoperazine and methadone both increase QTc interval. Modify Therapy/Monitor Closely.methadone and trifluoperazine both increase sedation. Use Caution/Monitor.methadone, trifluoperazine. 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).methamphetaminetrifluoperazine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, methamphetamine. 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.methocarbamolmethocarbamol and trifluoperazine both increase sedation. Use Caution/Monitor.methoxsalenmethoxsalen, trifluoperazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.methscopolaminemethscopolamine decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.methscopolamine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.methylenedioxymethamphetaminetrifluoperazine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, methylenedioxymethamphetamine. 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.methylergonovinemethylergonovine, trifluoperazine. 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).methylphenidatetrifluoperazine, methylphenidate. 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.trifluoperazine increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.metoclopramidetrifluoperazine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.midazolammidazolam and trifluoperazine both increase sedation. Use Caution/Monitor.midazolam intranasalmidazolam intranasal, trifluoperazine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.midodrinetrifluoperazine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, midodrine. 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.milnacipranmilnacipran, trifluoperazine. 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).mirtazapinetrifluoperazine and mirtazapine both increase sedation. Use Caution/Monitor.mirtazapine and trifluoperazine both decrease QTc interval. Use Caution/Monitor.modafiniltrifluoperazine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.morphinemorphine and trifluoperazine both increase sedation. Use Caution/Monitor.motherworttrifluoperazine and motherwort both increase sedation. Use Caution/Monitor.moxonidinetrifluoperazine and moxonidine both increase sedation. Use Caution/Monitor.nabilonetrifluoperazine and nabilone both increase sedation. Use Caution/Monitor.nalbuphinenalbuphine and trifluoperazine both increase sedation. Use Caution/Monitor.naratriptannaratriptan, trifluoperazine. 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).norepinephrinetrifluoperazine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, norepinephrine. 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.nortriptylinetrifluoperazine and nortriptyline both increase sedation. Use Caution/Monitor.ofloxacintrifluoperazine and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.olanzapineolanzapine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.olanzapine and trifluoperazine both increase sedation. Use Caution/Monitor.olanzapine and trifluoperazine both decrease QTc interval. Use Caution/Monitor.oliceridineoliceridine, trifluoperazine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. 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. Increased risk of hypotension if ability to maintain blood pressure has been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (eg, phenothiazines or general anesthetics).olodaterol inhaledtrifluoperazine and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. Drugs that prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmiasonabotulinumtoxinAonabotulinumtoxinA decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.onabotulinumtoxinA decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.opium tinctureopium tincture and trifluoperazine both increase sedation. Use Caution/Monitor.orphenadrineorphenadrine and trifluoperazine both increase sedation. Use Caution/Monitor.oxaliplatinoxaliplatin and trifluoperazine both decrease QTc interval. Use Caution/Monitor.oxazepamoxazepam and trifluoperazine both increase sedation. Use Caution/Monitor.oxybutyninoxybutynin decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.oxybutynin decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.oxybutynin topicaloxybutynin topical decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.oxybutynin topical decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.oxybutynin transdermaloxybutynin transdermal decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.oxybutynin transdermal decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.oxycodoneoxycodone and trifluoperazine both increase sedation. Use Caution/Monitor.oxymorphoneoxymorphone and trifluoperazine both increase sedation. Use Caution/Monitor.paliperidonepaliperidone and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.trifluoperazine and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely.paliperidone and trifluoperazine both increase sedation. Use Caution/Monitor.pancuroniumpancuronium decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.pancuronium decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.papaveretumpapaveretum and trifluoperazine both increase sedation. Use Caution/Monitor.papaverinetrifluoperazine and papaverine both increase sedation. Use Caution/Monitor.paroxetineparoxetine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.trifluoperazine and paroxetine both increase QTc interval. Modify Therapy/Monitor Closely.paroxetine, trifluoperazine. 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).pazopanibtrifluoperazine and pazopanib both increase QTc interval. Use Caution/Monitor.pentazocinepentazocine and trifluoperazine both increase sedation. Use Caution/Monitor.pentobarbitalpentobarbital and trifluoperazine both increase sedation. Use Caution/Monitor.perphenazineperphenazine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.perphenazine and trifluoperazine both increase sedation. Use Caution/Monitor.phendimetrazinetrifluoperazine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, 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.phenelzinephenelzine, trifluoperazine. 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).phenobarbitalphenobarbital and trifluoperazine both increase sedation. Use Caution/Monitor.phenterminetrifluoperazine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, 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.phenylephrinetrifluoperazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, 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.phenylephrine POtrifluoperazine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .trifluoperazine, 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.pholcodinetrifluoperazine and pholcodine both increase sedation. Use Caution/Monitor.pimozidepimozide and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.pimozide and trifluoperazine both increase sedation. Use Caution/Monitor.pirbuteroltrifluoperazine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.porfimertrifluoperazine, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.posaconazoletrifluoperazine and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.pralidoximepralidoxime decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.pralidoxime decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.primaquineprimaquine and trifluoperazine both decrease QTc interval. Use Caution/Monitor.primidoneprimidone and trifluoperazine both increase sedation. Use Caution/Monitor.procarbazineprocarbazine, trifluoperazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Excessive sedation.procarbazine, trifluoperazine. 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).prochlorperazineprochlorperazine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.prochlorperazine and trifluoperazine both increase sedation. Use Caution/Monitor.promethazinepromethazine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.promethazine and trifluoperazine both increase sedation. Use Caution/Monitor.promethazine, trifluoperazine. 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).propafenonepropafenone will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.propanthelinepropantheline decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.propantheline decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.trifluoperazine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.propofolpropofol and trifluoperazine both increase sedation. Use Caution/Monitor.propylhexedrinetrifluoperazine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.trifluoperazine, propylhexedrine. Mechanism: unknown. Use Caution/Monitor. Risk