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).dexamethasonedexamethasone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dexchlorpheniraminedexchlorpheniramine and quetiapine both increase sedation. Use Caution/Monitor.dexfenfluraminequetiapine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexmedetomidinedexmedetomidine and quetiapine both increase sedation. Use Caution/Monitor.dexmethylphenidatequetiapine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dextroamphetaminequetiapine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dextromethorphandextromethorphan, quetiapine. 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).dextromoramidedextromoramide and quetiapine both increase sedation. Use Caution/Monitor.DHEA, herbalDHEA, herbal will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.diamorphinediamorphine and quetiapine both increase sedation. Use Caution/Monitor.diazepamdiazepam and quetiapine both increase sedation. Use Caution/Monitor.dichlorphenamidedichlorphenamide and quetiapine both decrease serum potassium. Use Caution/Monitor.dicyclominedicyclomine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.dicyclomine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.quetiapine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.diethylpropionquetiapine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.difelikefalindifelikefalin and quetiapine both increase sedation. Use Caution/Monitor.difenoxin hcldifenoxin hcl and quetiapine both increase sedation. Use Caution/Monitor.dihydroergotaminedihydroergotamine, quetiapine. 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).diltiazemdiltiazem will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.dimenhydrinatedimenhydrinate and quetiapine both increase sedation. Use Caution/Monitor.diphenhydraminediphenhydramine and quetiapine both increase sedation. Use Caution/Monitor.diphenhydramine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.diphenhydramine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.quetiapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.diphenoxylate hcldiphenoxylate hcl and quetiapine both increase sedation. Use Caution/Monitor.dipipanonedipipanone and quetiapine both increase sedation. Use Caution/Monitor.disopyramidequetiapine, disopyramide. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.dobutaminequetiapine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dofetilidequetiapine, dofetilide. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.dofetilide increases toxicity of quetiapine by QTc interval. Use Caution/Monitor.dolasetronquetiapine, dolasetron. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.donepezil transdermalquetiapine, donepezil transdermal. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.dopaminequetiapine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dopexaminequetiapine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dosulepinquetiapine and dosulepin both increase sedation. Use Caution/Monitor.doxepinquetiapine and doxepin both increase sedation. Use Caution/Monitor.doxepin and quetiapine both increase QTc interval. Use Caution/Monitor.doxylaminedoxylamine and quetiapine both increase sedation. Use Caution/Monitor.dronedaronedronedarone will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.quetiapine, dronedarone. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.droperidoldroperidol and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.droperidol and quetiapine both increase sedation. Use Caution/Monitor.quetiapine, droperidol. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.duvelisibduvelisib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.efavirenzefavirenz will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.elagolixelagolix decreases levels of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.eletriptaneletriptan, quetiapine. 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).encorafenibencorafenib, quetiapine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.ephedrinequetiapine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrinequetiapine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrine racemicquetiapine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ergoloid mesylatesergoloid mesylates, quetiapine. 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).ergotamineergotamine, quetiapine. 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).erythromycin basequetiapine, erythromycin base. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.erythromycin ethylsuccinatequetiapine, erythromycin ethylsuccinate. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.erythromycin lactobionatequetiapine, erythromycin lactobionate. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.erythromycin stearatequetiapine, erythromycin stearate. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.escitalopramquetiapine, escitalopram. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.esketamine intranasalesketamine intranasal, quetiapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.eslicarbazepine acetateeslicarbazepine acetate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.estazolamestazolam and quetiapine both increase sedation. Use Caution/Monitor.ethanolquetiapine and ethanol both increase sedation. Use Caution/Monitor.etravirineetravirine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.exenatide injectable solutionquetiapine, exenatide injectable solution. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.exenatide injectable suspensionquetiapine, exenatide injectable suspension. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.ezogabineezogabine, quetiapine. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.fedratinibfedratinib will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.fenfluraminequetiapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.quetiapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.fentanylfentanyl, quetiapine. 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).fesoterodinefesoterodine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.fesoterodine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.quetiapine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.flavoxateflavoxate decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.flavoxate decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.quetiapine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.flecainidequetiapine, flecainide. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.flibanserinflibanserin, quetiapine. 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).fluconazolefluconazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.quetiapine, fluconazole. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.fludrocortisonefludrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluoxetinequetiapine, fluoxetine. Either increases toxicity of the other by QTc