oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. oliceridine, thioridazine. 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 inhaledMonitor Closely (1)thioridazine 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 arrhythmiasolopatadine intranasalSerious - Use Alternative (1)thioridazine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. omaveloxoloneMonitor Closely (1)omaveloxolone will decrease the level or effect of thioridazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Omaveloxolone may reduce systemic exposure of sensitive CYP3A4 substrates. Check prescribing information of substrate if dosage modification is needed. onabotulinumtoxinAMonitor Closely (3)onabotulinumtoxinA decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. onabotulinumtoxinA decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.ondansetronSerious - Use Alternative (1)thioridazine and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.opium tinctureMonitor Closely (1)opium tincture and thioridazine both increase sedation. Use Caution/Monitor.orphenadrineMonitor Closely (1)orphenadrine and thioridazine both increase sedation. Use Caution/Monitor.osilodrostatMonitor Closely (1)osilodrostat and thioridazine both increase QTc interval. Use Caution/Monitor.osimertinibMonitor Closely (1)osimertinib and thioridazine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.oxaliplatinContraindicated (1)oxaliplatin and thioridazine both increase QTc interval. Contraindicated.Monitor Closely (1)oxaliplatin will increase the level or effect of thioridazine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.oxazepamMonitor Closely (1)oxazepam and thioridazine both increase sedation. Use Caution/Monitor.oxybutyninMonitor Closely (3)oxybutynin decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin increases toxicity of thioridazine by unspecified interaction mechanism. Minor/Significance Unknown.oxybutynin topicalMonitor Closely (3)oxybutynin topical decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin topical decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin topical increases toxicity of thioridazine by unspecified interaction mechanism. Minor/Significance Unknown.oxybutynin transdermalMonitor Closely (3)oxybutynin transdermal decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. oxybutynin transdermal decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)oxybutynin transdermal increases toxicity of thioridazine by unspecified interaction mechanism. Minor/Significance Unknown.oxycodoneMonitor Closely (2)thioridazine will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. oxycodone and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases effects of oxycodone by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of oxycodone to active metabolite morphine.oxymorphoneMonitor Closely (2)thioridazine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. oxymorphone and thioridazine both increase sedation. Use Caution/Monitor.ozanimodMonitor Closely (1)ozanimod and thioridazine 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)thioridazine and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely. paliperidone and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. paliperidone and thioridazine both increase sedation. Use Caution/Monitor.pancuroniumMonitor Closely (3)pancuronium decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. pancuronium decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine 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 thioridazine 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.Serious - Use Alternative (1)thioridazine and panobinostat both increase QTc interval. Avoid or Use Alternate Drug. Panobinostat is known to significantly prolong QT interval. Panobinostat prescribing information states use with drugs known to prolong QTc is not recommended.papaveretumMonitor Closely (1)papaveretum and thioridazine both increase sedation. Use Caution/Monitor.papaverineMonitor Closely (1)thioridazine and papaverine both increase sedation. Use Caution/Monitor.parecoxibSerious - Use Alternative (1)parecoxib will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.paroxetineContraindicated (1)paroxetine increases levels of thioridazine by decreasing metabolism. Contraindicated. Risk of long QT syndrome.Serious - Use Alternative (3)paroxetine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. thioridazine will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. thioridazine and paroxetine both increase QTc interval. Avoid or Use Alternate Drug.pasireotideContraindicated (1)thioridazine and pasireotide both increase QTc interval. Contraindicated.pazopanibMonitor Closely (1)thioridazine and pazopanib both increase QTc interval. Use Caution/Monitor.peginterferon alfa 2bMonitor Closely (1)peginterferon alfa 2b, thioridazine. 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)thioridazine and pentamidine both increase QTc interval. Contraindicated.pentazocineMonitor Closely (1)pentazocine and thioridazine both increase sedation. Use Caution/Monitor.pentobarbitalMonitor Closely (1)pentobarbital and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases levels of pentobarbital by unspecified interaction mechanism. Minor/Significance Unknown.perhexilineMinor (1)thioridazine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.perindoprilMinor (1)thioridazine increases effects of perindopril by unspecified interaction mechanism. Minor/Significance Unknown.perphenazineMonitor Closely (2)perphenazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. perphenazine and thioridazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (2)perphenazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug. perphenazine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.Minor (1)thioridazine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.phendimetrazineMonitor Closely (2)thioridazine, 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. thioridazine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenobarbitalMonitor Closely (1)phenobarbital and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases levels of phenobarbital by unspecified interaction mechanism. Minor/Significance Unknown.phentermineMonitor Closely (2)thioridazine, 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. thioridazine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrineMonitor Closely (2)thioridazine, 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. thioridazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrine POMonitor Closely (2)thioridazine, 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. thioridazine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .pholcodineMonitor Closely (1)thioridazine and pholcodine both increase sedation. Use Caution/Monitor.pimavanserinSerious - Use Alternative (1)pimavanserin and thioridazine both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.pimozideContraindicated (1)thioridazine and pimozide both increase QTc interval. Contraindicated.Monitor Closely (2)pimozide and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. pimozide and thioridazine both increase sedation. Use Caution/Monitor.pirbuterolMonitor Closely (1)thioridazine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.pitolisantMonitor Closely (1)thioridazine will increase the level or effect of pitolisant by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If coadministered with strong CYP2D6 inhibitors, initiate pitolisant at 8.9 mg/day and increase after 7 days to maximum of 17.8 mg/day. For patients currently taking pitolisant, reduce pitolisant dose by half upon initiating strong CYP2D6 inhibitors.Serious - Use Alternative (1)thioridazine and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.porfimerMonitor Closely (1)thioridazine, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.posaconazoleMonitor Closely (1)thioridazine and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.pralidoximeMonitor Closely (3)pralidoxime decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. pralidoxime decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.pramipexoleSerious - Use Alternative (1)thioridazine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.primaquineContraindicated (1)primaquine and thioridazine both increase QTc interval. Contraindicated.primidoneMonitor Closely (1)primidone and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases levels of primidone by unspecified interaction mechanism. Minor/Significance Unknown.procainamideContraindicated (1)thioridazine and procainamide both increase QTc interval. Contraindicated.procarbazineMonitor Closely (1)procarbazine, thioridazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Excessive sedation.prochlorperazineMonitor Closely (2)prochlorperazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. prochlorperazine and thioridazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)prochlorperazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)thioridazine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.promazineSerious - Use Alternative (1)promazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)thioridazine will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.promethazineMonitor Closely (2)promethazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. promethazine and thioridazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)promethazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)thioridazine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.propafenoneSerious - Use Alternative (2)propafenone will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. The concurrent administration of thioridazine and agents that prolong the QT interval, such as Class I antiarrhythmic agents, is contraindicated. thioridazine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. The concurrent administration of thioridazine and agents that prolong the QT interval, such as Class I antiarrhythmic agents, is contraindicated.propanthelineMonitor Closely (3)propantheline decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. propantheline decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.propofolMonitor Closely (1)propofol and thioridazine both increase sedation. Use Caution/Monitor.propranololSerious - Use Alternative (2)thioridazine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Due to the potential for significant, possibly life-threatening, proarrhythmic effects, concurrent administration of thioridazine and propranolol is contraindicated. propranolol, thioridazine. Either increases levels of the other by decreasing metabolism. Contraindicated. Not all beta blockers share this interaction (e.g., atenolol, nadolol, sotalol do not interact).propylhexedrineMonitor Closely (2)thioridazine, 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. thioridazine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.protriptylineMonitor Closely (1)thioridazine and protriptyline both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)thioridazine and protriptyline both increase QTc interval. Avoid