and opium and thioridazine both increase sedation. Use Caution/Monitor.benazeprilMinor (1)thioridazine, benazepril. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. May increase risk of hypotension.benperidolMonitor Closely (2)benperidol and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. benperidol and thioridazine both increase sedation. Use Caution/Monitor.benzhydrocodone/acetaminophenMonitor Closely (1)thioridazine will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone [benzhydrocodone is prodrug of hydrocodone]) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.Serious - Use Alternative (2)benzhydrocodone/acetaminophen, thioridazine. Either increases toxicity 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. 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). benzhydrocodone/acetaminophen and thioridazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebenzphetamineMonitor Closely (2)thioridazine, benzphetamine. 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 benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benztropineMonitor Closely (1)thioridazine increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .berotralstatMonitor Closely (1)berotralstat will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Monitor or titrate substrate dose when berotralstat is coadministered with narrow therapeutic index drugs that are CYP2D6 substrates.bremelanotideSerious - Use Alternative (1)bremelanotide will decrease the level or effect of thioridazine by Other (see comment). Avoid or Use Alternate Drug. Bremelanotide may slow gastric emptying and potentially reduces the rate and extent of absorption of concomitantly administered oral medications. Avoid use when taking any oral drug that is dependent on threshold concentrations for efficacy. Interactions listed are representative examples and do not include all possible clinical examples.brexanoloneMonitor Closely (1)brexanolone, thioridazine. Either increases toxicity of the other by sedation. Use Caution/Monitor.brexpiprazoleMonitor Closely (2)thioridazine will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP2D6 inhibitor PLUS a strong/moderate CYP3A4 inhibitor. brexpiprazole and thioridazine both increase sedation. Use Caution/Monitor.brimonidineMonitor Closely (1)brimonidine and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)brimonidine increases effects of thioridazine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.brivaracetamMonitor Closely (1)brivaracetam and thioridazine both increase sedation. Use Caution/Monitor.bromocriptineSerious - Use Alternative (1)thioridazine decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.brompheniramineMonitor Closely (1)brompheniramine and thioridazine both increase sedation. Use Caution/Monitor.buprenorphineContraindicated (1)buprenorphine and thioridazine both increase QTc interval. Contraindicated.Monitor Closely (1)buprenorphine and thioridazine both increase sedation. Use Caution/Monitor.buprenorphine buccalContraindicated (1)buprenorphine buccal and thioridazine both increase QTc interval. Contraindicated.Monitor Closely (1)buprenorphine buccal and thioridazine both increase sedation. Use Caution/Monitor.buprenorphine subdermal implantContraindicated (1)buprenorphine subdermal implant and thioridazine both increase QTc interval. Contraindicated.Serious - Use Alternative (1)buprenorphine subdermal implant and thioridazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebuprenorphine transdermalContraindicated (1)buprenorphine transdermal and thioridazine both increase QTc interval. Contraindicated.Serious - Use Alternative (1)buprenorphine transdermal and thioridazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebuprenorphine, long-acting injectionContraindicated (1)buprenorphine, long-acting injection and thioridazine both increase QTc interval. Contraindicated.Monitor Closely (1)thioridazine 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.Serious - Use Alternative (1)buprenorphine, long-acting injection and thioridazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequatebupropionSerious - Use Alternative (1)bupropion will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.Minor (1)thioridazine increases toxicity of bupropion by unspecified interaction mechanism. Minor/Significance Unknown. May lower seizure threshold; keep bupropion dose as low as possible.butabarbitalMonitor Closely (1)butabarbital and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases levels of butabarbital by unspecified interaction mechanism. Minor/Significance Unknown.butalbitalMonitor Closely (1)butalbital and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases levels of butalbital by unspecified interaction mechanism. Minor/Significance Unknown.butorphanolMonitor Closely (1)butorphanol and thioridazine both increase sedation. Use Caution/Monitor.cabergolineSerious - Use Alternative (1)thioridazine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.caffeineMonitor Closely (1)thioridazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.calcium/magnesium/potassium/sodium oxybatesSerious - Use Alternative (1)thioridazine, 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)thioridazine increases effects of captopril by unspecified interaction mechanism. Minor/Significance Unknown.carbinoxamineMonitor Closely (1)carbinoxamine and thioridazine both increase sedation. Use Caution/Monitor.carisoprodolMonitor Closely (1)carisoprodol and thioridazine both increase sedation. Use Caution/Monitor.carvedilolMonitor Closely (1)thioridazine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)carvedilol, 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).celecoxibSerious - Use Alternative (1)celecoxib will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.cenobamateMonitor Closely (1)cenobamate, thioridazine. Either increases effects of the other by sedation. Use Caution/Monitor.ceritinibContraindicated (1)ceritinib and thioridazine both increase QTc interval. Contraindicated.chasteberryMinor (1)chasteberry decreases effects of thioridazine by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).chloral hydrateMonitor Closely (1)chloral hydrate and thioridazine both increase sedation. Use Caution/Monitor.chlordiazepoxideMonitor Closely (1)chlordiazepoxide and thioridazine both increase sedation. Use Caution/Monitor.chloroquineMonitor Closely (1)chloroquine increases toxicity of thioridazine by QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)chloroquine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.Minor (1)chloroquine increases levels of thioridazine by decreasing metabolism. Minor/Significance Unknown.chlorpheniramineMonitor Closely (1)chlorpheniramine and thioridazine both increase sedation. Use Caution/Monitor.chlorpromazineMonitor Closely (2)chlorpromazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. chlorpromazine and thioridazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)chlorpromazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)thioridazine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.chlorzoxazoneMonitor Closely (1)chlorzoxazone and thioridazine both increase sedation. Use Caution/Monitor.cigarette smokingMonitor Closely (1)cigarette smoking decreases levels of thioridazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.cimetidineSerious - Use Alternative (1)cimetidine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.cinnarizineMonitor Closely (1)cinnarizine and thioridazine both increase sedation. Use Caution/Monitor.ciprofloxacinMonitor Closely (1)ciprofloxacin and thioridazine both increase QTc interval. Use Caution/Monitor. Ciprofloxacin elicits minimal effects on QT interval. Caution if used in combination with other drugs known to affect QT interval or in patients with other risk factors.cisatracuriumMonitor Closely (3)cisatracurium decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. cisatracurium decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.citalopramSerious - Use Alternative (1)thioridazine and citalopram both increase QTc interval. Avoid or Use Alternate Drug. Thioridazine should be avoided in combination with drugs that are known to prolong QTc interval.clarithromycinSerious - Use Alternative (1)thioridazine and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.clemastineMonitor Closely (1)clemastine and thioridazine both increase sedation. Use Caution/Monitor.clobazamMonitor Closely (2)clobazam will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly. thioridazine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).clomipramineContraindicated (1)thioridazine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.Monitor Closely (1)thioridazine and clomipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)thioridazine and clomipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)clomipramine, thioridazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. clomipramine, thioridazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.clonazepamMonitor Closely (1)clonazepam and thioridazine both increase sedation. Use Caution/Monitor.clonidineMonitor Closely (1)clonidine, thioridazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.clorazepateMonitor Closely (1)clorazepate and thioridazine both increase sedation. Use Caution/Monitor.clozapineContraindicated (1)clozapine and thioridazine both increase QTc interval. Contraindicated.Monitor Closely (2)clozapine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. clozapine and thioridazine both increase sedation. Use Caution/Monitor.cobicistatMonitor Closely (1)cobicistat will increase the level or effect of thioridazine 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. codeineMonitor Closely (2)thioridazine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine. codeine and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.crizotinibContraindicated (1)crizotinib and thioridazine both increase QTc interval. Contraindicated. Thioridazine is contraindicated with drugs that may prolong the QT interval.cyclizineMonitor Closely (4)cyclizine decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. cyclizine decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of cyclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. cyclizine and thioridazine both increase sedation. Use Caution/Monitor.cyclobenzaprineMonitor Closely (4)cyclobenzaprine decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. cyclobenzaprine decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of cyclobenzaprine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. cyclobenzaprine and thioridazine both increase sedation. Use Caution/Monitor.cyproheptadineMonitor Closely (1)cyproheptadine and thioridazine both increase sedation. Use Caution/Monitor.dacomitinibSerious - Use Alternative (1)dacomitinib will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities. dantroleneMonitor Closely (1)dantrolene and thioridazine both increase sedation. Use Caution/Monitor.daridorexantMonitor Closely (1)thioridazine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. darifenacinMonitor Closely (3)darifenacin decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. darifenacin decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor. thioridazine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Serious - Use Alternative (1)darifenacin will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.dasatinibMonitor Closely (1)thioridazine and dasatinib both increase QTc interval. Modify Therapy/Monitor Closely.degarelixContraindicated (1)degarelix and thioridazine both increase QTc interval. Contraindicated.desfluraneMonitor Closely (1)desflurane and thioridazine both increase sedation. Use Caution/Monitor.desipramineContraindicated (1)thioridazine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated.Monitor Closely (1)thioridazine and desipramine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)thioridazine and desipramine both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)desipramine, thioridazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. desipramine, thioridazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown.