level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.thioridazine and venlafaxine both increase QTc interval. Avoid or Use Alternate Drug.vilanterol/fluticasone furoate inhaledthioridazine increases toxicity of vilanterol/fluticasone furoate inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.yohimbeyohimbe decreases effects of thioridazine by pharmacodynamic antagonism. Contraindicated.ziprasidonethioridazine and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.Monitor Closely (327)abirateroneabiraterone increases levels of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.abobotulinumtoxinAabobotulinumtoxinA increases effects of thioridazine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.aclidiniumaclidinium decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.acrivastineacrivastine and thioridazine both increase sedation. Use Caution/Monitor.albiglutidethioridazine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.albuterolthioridazine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.alfentanilalfentanil and thioridazine both increase sedation. Use Caution/Monitor.alfuzosinthioridazine and alfuzosin both increase QTc interval. Use Caution/Monitor.alprazolamalprazolam and thioridazine both increase sedation. Use Caution/Monitor.amifampridinethioridazine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.amitriptylinethioridazine and amitriptyline both increase sedation. Use Caution/Monitor.amobarbitalamobarbital and thioridazine both increase sedation. Use Caution/Monitor.amoxapinethioridazine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.thioridazine and amoxapine both increase sedation. Use Caution/Monitor.anticholinergic/sedative combosanticholinergic/sedative combos decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.anticholinergic/sedative combos decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.arformoterolthioridazine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.aripiprazolearipiprazole and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.aripiprazole and thioridazine both increase sedation. Use Caution/Monitor.armodafinilthioridazine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.asenapineasenapine and thioridazine both increase sedation. Use Caution/Monitor.asenapine transdermalasenapine transdermal and thioridazine both increase sedation. Use Caution/Monitor.atomoxetinethioridazine will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.atracuriumatracurium decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.atracurium decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.atropineatropine decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.atropine decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.atropine IV/IMthioridazine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.atropine IV/IM decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.atropine IV/IM decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.avapritinibavapritinib and thioridazine both increase sedation. Use Caution/Monitor.azelastineazelastine and thioridazine both increase sedation. Use Caution/Monitor.azithromycinthioridazine and azithromycin both increase QTc interval. Use Caution/Monitor.baclofenbaclofen and thioridazine both increase sedation. Use Caution/Monitor.bedaquilinethioridazine and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closelybelladonna alkaloidsbelladonna alkaloids decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.belladonna alkaloids decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of belladonna alkaloids by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.belladonna and opiumbelladonna and opium and thioridazine both increase sedation. Use Caution/Monitor.belladonna and opium decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.belladonna and opium decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.thioridazine increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.benperidolbenperidol 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/acetaminophenthioridazine 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.benzphetaminethioridazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.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.benztropinethioridazine increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .berotralstatberotralstat 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.brexanolonebrexanolone, thioridazine. Either increases toxicity of the other by sedation. Use Caution/Monitor.brexpiprazolethioridazine 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.brimonidinebrimonidine and thioridazine both increase sedation. Use Caution/Monitor.brivaracetambrivaracetam and thioridazine both increase sedation. Use Caution/Monitor.brompheniraminebrompheniramine and thioridazine both increase sedation. Use Caution/Monitor.buprenorphinebuprenorphine and thioridazine both increase sedation. Use Caution/Monitor.buprenorphine buccalbuprenorphine buccal and thioridazine both increase sedation. Use Caution/Monitor.buprenorphine, long-acting injectionthioridazine 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.butabarbitalbutabarbital and thioridazine both increase sedation. Use Caution/Monitor.butalbitalbutalbital and thioridazine both increase sedation. Use Caution/Monitor.butorphanolbutorphanol and thioridazine both increase sedation. Use Caution/Monitor.caffeinethioridazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.carbinoxaminecarbinoxamine and thioridazine both increase sedation. Use Caution/Monitor.carisoprodolcarisoprodol and thioridazine both increase sedation. Use Caution/Monitor.carvedilolthioridazine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.cenobamatecenobamate, thioridazine. Either increases effects of the other by sedation. Use Caution/Monitor.chloral hydratechloral hydrate and thioridazine both increase sedation. Use Caution/Monitor.chlordiazepoxidechlordiazepoxide and thioridazine both increase sedation. Use Caution/Monitor.chloroquinechloroquine increases toxicity of thioridazine by QTc interval. Use Caution/Monitor.chlorpheniraminechlorpheniramine and thioridazine both increase sedation. Use Caution/Monitor.chlorpromazinechlorpromazine 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.chlorzoxazonechlorzoxazone and thioridazine both increase sedation. Use Caution/Monitor.cigarette smokingcigarette smoking decreases levels of thioridazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.cinnarizinecinnarizine and thioridazine both increase sedation. Use Caution/Monitor.ciprofloxacinciprofloxacin 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.cisatracuriumcisatracurium 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.clemastineclemastine and thioridazine both increase sedation. Use Caution/Monitor.clobazamclobazam 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).clomipraminethioridazine and clomipramine both increase sedation. Use Caution/Monitor.clonazepamclonazepam and thioridazine both increase sedation. Use Caution/Monitor.clonidineclonidine, thioridazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.clorazepateclorazepate and thioridazine both increase sedation. Use Caution/Monitor.clozapineclozapine 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.cobicistatcobicistat 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. codeinethioridazine 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.cyclizinecyclizine and thioridazine both increase sedation. Use Caution/Monitor.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.cyclobenzaprinecyclobenzaprine and thioridazine both increase sedation. Use Caution/Monitor.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.cyproheptadinecyproheptadine and thioridazine both increase sedation. Use Caution/Monitor.dantrolenedantrolene and thioridazine both increase sedation. Use Caution/Monitor.daridorexantthioridazine 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. darifenacindarifenacin 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.dasatinibthioridazine and dasatinib both increase QTc interval. Modify Therapy/Monitor Closely.desfluranedesflurane and thioridazine both increase sedation. Use Caution/Monitor.desipraminethioridazine and desipramine both increase sedation. Use Caution/Monitor.desvenlafaxinedesvenlafaxine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mgdeutetrabenazinethioridazine and deutetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely. The risk for parkinsonism, neuroleptic malignant syndrome, and akathisia may be increased by concomitant use of deutetrabenazine and dopamine antagonists or antipsychotics.thioridazine and deutetrabenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).thioridazine will increase the level or effect of deutetrabenazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Strong CYP2D6 inhibitors increase the systemic exposure to the active dihydro-metabolites of deutetrabenazine by approximately 3-fold. Do not exceed 18 mg/dose and 36 mg/day of deutetrabenazine if coadministered with strong CYP2D6 inhibitors.dexchlorpheniraminedexchlorpheniramine and thioridazine both increase sedation. Use Caution/Monitor.dexfenfluraminethioridazine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.thioridazine, dexfenfluramine. 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.dexmedetomidinedexmedetomidine and thioridazine both increase sedation. Use Caution/Monitor.dexmethylphenidatethioridazine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.thioridazine, dexmethylphenidate. 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.dextroamphetaminethioridazine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.thioridazine, dextroamphetamine. 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.dextroamphetamine transdermalthioridazine will increase the level or effect of dextroamphetamine transdermal by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome, particularly during dextroamphetamine initiation and after a dosage increase.