level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.erythromycin stearateMonitor Closely (1)quetiapine, 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.Serious - Use Alternative (1)erythromycin stearate will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.escitalopramMonitor Closely (1)quetiapine, 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.Serious - Use Alternative (1)escitalopram increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug.esketamine intranasalMonitor Closely (1)esketamine intranasal, quetiapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.eslicarbazepine acetateMonitor Closely (1)eslicarbazepine acetate will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.estazolamMonitor Closely (1)estazolam and quetiapine both increase sedation. Use Caution/Monitor.ethanolMonitor Closely (1)quetiapine and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol, quetiapine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.etravirineMonitor Closely (1)etravirine will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.eucalyptusMinor (1)quetiapine and eucalyptus both increase sedation. Minor/Significance Unknown.exenatide injectable solutionMonitor Closely (1)quetiapine, 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 suspensionMonitor Closely (1)quetiapine, 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.ezogabineMonitor Closely (1)ezogabine, 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.fedratinibMonitor Closely (1)fedratinib 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.fenfluramineMonitor Closely (2)quetiapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. quetiapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fentanylMonitor Closely (1)fentanyl, 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).fesoterodineMonitor Closely (3)fesoterodine 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.fexinidazoleSerious - Use Alternative (2)fexinidazole and quetiapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels and/or prolong QT interval. fexinidazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.fingolimodSerious - Use Alternative (1)fingolimod and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.flavoxateMonitor Closely (3)flavoxate 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.flecainideMonitor Closely (1)quetiapine, 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.flibanserinMonitor Closely (1)flibanserin, 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).fluconazoleMonitor Closely (2)fluconazole 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.fludrocortisoneMonitor Closely (1)fludrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluoxetineMonitor Closely (1)quetiapine, fluoxetine. 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.fluphenazineMonitor Closely (2)fluphenazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. fluphenazine and quetiapine both increase sedation. Use Caution/Monitor.flurazepamMonitor Closely (1)flurazepam and quetiapine both increase sedation. Use Caution/Monitor.fluvoxamineMonitor Closely (1)fluvoxamine will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.formoterolMonitor Closely (1)quetiapine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.fosamprenavirMonitor Closely (1)fosamprenavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosaprepitantMonitor Closely (1)fosaprepitant will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.foscarnetMonitor Closely (1)quetiapine, foscarnet. 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.fosphenytoinMonitor Closely (1)fosphenytoin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fostemsavirMonitor Closely (1)quetiapine and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir. frovatriptanMonitor Closely (1)frovatriptan, 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).gadobenateMonitor Closely (1)gadobenate and quetiapine both increase QTc interval. Use Caution/Monitor.ganaxoloneMonitor Closely (1)quetiapine and ganaxolone both increase sedation. Use Caution/Monitor.gemifloxacinMonitor Closely (1)quetiapine, gemifloxacin. 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.gemtuzumabMonitor Closely (1)quetiapine and gemtuzumab both increase QTc interval. Use Caution/Monitor.gilteritinibSerious - Use Alternative (1)gilteritinib and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.glasdegibSerious - Use Alternative (1)quetiapine and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.glimepirideMonitor Closely (1)quetiapine, glimepiride. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.glipizideMonitor Closely (1)quetiapine, glipizide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.glyburideMonitor Closely (1)quetiapine, glyburide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.glycopyrrolateMonitor Closely (1)quetiapine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.glycopyrrolate inhaledMonitor Closely (3)glycopyrrolate inhaled decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. glycopyrrolate inhaled decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor. quetiapine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.goserelinContraindicated (1)goserelin increases toxicity of quetiapine by QTc interval. Contraindicated. Increases risk of torsades de pointes.granisetronSerious - Use Alternative (1)granisetron and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.grapefruitMonitor Closely (1)grapefruit will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.griseofulvinMonitor Closely (1)griseofulvin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.guanfacineMonitor Closely (1)guanfacine, quetiapine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.haloperidolMonitor Closely (3)haloperidol and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. haloperidol and quetiapine both increase sedation. Use Caution/Monitor. quetiapine, haloperidol. 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.hawthornMonitor Closely (1)quetiapine, hawthorn. 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.henbaneMonitor Closely (3)henbane decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. henbane decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor. quetiapine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.histrelinSerious - Use Alternative (1)histrelin increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.homatropineMonitor Closely (3)homatropine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. homatropine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor. quetiapine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hydrocodoneSerious - Use Alternative (1)hydrocodone, quetiapine. 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.hydrocortisoneMonitor Closely (1)hydrocortisone will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.hydromorphoneMonitor Closely (1)hydromorphone and quetiapine both increase sedation. Use Caution/Monitor.hydroxychloroquine sulfateSerious - Use Alternative (1)hydroxychloroquine sulfate and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.hydroxyzineMonitor Closely (1)hydroxyzine and quetiapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)hydroxyzine increases toxicity of quetiapine by QTc interval. Avoid or Use Alternate Drug. Increases risk of torsades de pointes.hyoscyamineMonitor Closely (3)hyoscyamine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. hyoscyamine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor. quetiapine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine sprayMonitor Closely (3)quetiapine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. hyoscyamine spray decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. hyoscyamine spray decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.ibutilideMonitor Closely (1)quetiapine, ibutilide. 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