drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation). olanzapine 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.dexchlorpheniramineMonitor Closely (1)dexchlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.dexfenfluramineMonitor Closely (1)olanzapine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexmedetomidineMonitor Closely (1)dexmedetomidine and olanzapine both increase sedation. Use Caution/Monitor.dexmethylphenidateMonitor Closely (1)olanzapine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dextroamphetamineMonitor Closely (1)olanzapine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dextromethorphanMonitor Closely (1)dextromethorphan, olanzapine. 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).dextromoramideMonitor Closely (1)dextromoramide and olanzapine both increase sedation. Use Caution/Monitor.diamorphineMonitor Closely (1)diamorphine and olanzapine both increase sedation. Use Caution/Monitor.diazepamMonitor Closely (1)diazepam and olanzapine both increase sedation. Use Caution/Monitor.diazepam intranasalSerious - Use Alternative (1)diazepam intranasal, samidorphan. 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.dicyclomineMonitor Closely (3)dicyclomine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. dicyclomine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor. olanzapine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.diethylpropionMonitor Closely (1)olanzapine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.difelikefalinMonitor Closely (2)difelikefalin and samidorphan both increase sedation. Use Caution/Monitor. difelikefalin and olanzapine both increase sedation. Use Caution/Monitor.difenoxin hclMonitor Closely (1)difenoxin hcl and olanzapine both increase sedation. Use Caution/Monitor.dihydroergotamineMonitor Closely (1)dihydroergotamine, olanzapine. 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).dimenhydrinateMonitor Closely (1)dimenhydrinate and olanzapine both increase sedation. Use Caution/Monitor.diphenhydramineMonitor Closely (4)diphenhydramine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. diphenhydramine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor. olanzapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. diphenhydramine and olanzapine both increase sedation. Use Caution/Monitor.diphenoxylate hclMonitor Closely (1)diphenoxylate hcl and olanzapine both increase sedation. Use Caution/Monitor.dipipanoneMonitor Closely (1)dipipanone and olanzapine both increase sedation. Use Caution/Monitor.disopyramideSerious - Use Alternative (1)olanzapine and disopyramide both increase QTc interval. Avoid or Use Alternate Drug.dobutamineMonitor Closely (1)olanzapine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dofetilideMonitor Closely (1)dofetilide increases toxicity of olanzapine by QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.dolasetronMonitor Closely (1)dolasetron and olanzapine both increase QTc interval. Use Caution/Monitor.donepezilMonitor Closely (1)donepezil and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesdopamineMonitor Closely (1)olanzapine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.dopexamineMonitor Closely (1)olanzapine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dosulepinMonitor Closely (1)olanzapine and dosulepin both increase sedation. Use Caution/Monitor.doxepinMonitor Closely (2)doxepin and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances olanzapine and doxepin both increase sedation. Use Caution/Monitor.doxylamineMonitor Closely (1)doxylamine and olanzapine both increase sedation. Use Caution/Monitor.dronedaroneContraindicated (1)olanzapine and dronedarone both increase QTc interval. Contraindicated.droperidolMonitor Closely (2)droperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor. droperidol and olanzapine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and droperidol both increase QTc interval. Avoid or Use Alternate Drug.efavirenzMonitor Closely (1)efavirenz and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instanceseletriptanMonitor Closely (1)eletriptan, olanzapine. 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).eliglustatSerious - Use Alternative (1)olanzapine and eliglustat both increase QTc interval. Avoid or Use Alternate Drug.encorafenibSerious - Use Alternative (1)encorafenib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesentrectinibSerious - Use Alternative (1)olanzapine and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.epcoritamabMonitor Closely (1)epcoritamab, olanzapine. affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Epcoritamab causes release of cytokines that may suppress activity of CYP enzymes, resulting in increased exposure of CYP substrates. For certain CYP substrates, minimal changes in their concentration may lead to serious adverse reactions. If needed, modify therapy as recommended in the substrate's prescribing information. .ephedrineMonitor Closely (1)olanzapine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrineMonitor Closely (1)olanzapine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.epinephrine racemicMonitor Closely (1)olanzapine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.erdafitinibSerious - Use Alternative (1)olanzapine will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.ergoloid mesylatesMonitor Closely (1)ergoloid mesylates, olanzapine. 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).ergotamineMonitor Closely (1)ergotamine, olanzapine. 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).eribulinSerious - Use Alternative (1)eribulin and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instanceserythromycin baseMonitor Closely (1)erythromycin base will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.erythromycin ethylsuccinateMonitor Closely (1)erythromycin ethylsuccinate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.erythromycin lactobionateMonitor Closely (1)erythromycin lactobionate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.erythromycin stearateMonitor Closely (1)erythromycin stearate will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)olanzapine and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.escitalopramMonitor Closely (1)escitalopram increases toxicity of olanzapine by QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances.esketamine intranasalMonitor Closely (1)esketamine intranasal, olanzapine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.estazolamMonitor Closely (1)estazolam and olanzapine both increase sedation. Use Caution/Monitor.ethanolMonitor Closely (1)olanzapine and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.ethinylestradiolMonitor Closely (1)ethinylestradiol will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.eucalyptusMinor (1)olanzapine and eucalyptus both increase sedation. Minor/Significance Unknown.exenatide injectable solutionMonitor Closely (1)olanzapine, 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)olanzapine, 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.fedratinibSerious - Use Alternative (1)olanzapine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.fenfluramineMonitor Closely (3)olanzapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. olanzapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. samidorphan decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.fentanylMonitor Closely (1)fentanyl, olanzapine. 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 olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. fesoterodine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor. olanzapine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.fexinidazoleMonitor Closely (1)fexinidazole will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fexinidazole and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.fezolinetantContraindicated (1)olanzapine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitorsfinerenoneMonitor Closely (1)olanzapine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.fingolimodMonitor Closely (1)fingolimod and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instancesflavoxateMonitor Closely (3)flavoxate decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. flavoxate decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor. olanzapine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.flecainideMonitor Closely (1)olanzapine and flecainide both increase QTc interval. Use Caution/Monitor.flibanserinMonitor Closely (2)olanzapine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak