rare instancesdesipramineMonitor Closely (3)olanzapine and desipramine both increase sedation. Use Caution/Monitor. olanzapine and desipramine both increase QTc interval. Use Caution/Monitor. desipramine and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (2)fluoxetine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. fluoxetine and desipramine both increase serotonin levels. Avoid or Use Alternate Drug.desvenlafaxineMonitor Closely (1)desvenlafaxine will increase the level or effect of fluoxetine 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 mgSerious - Use Alternative (1)fluoxetine and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.deutetrabenazineMonitor Closely (5)deutetrabenazine and olanzapine 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). fluoxetine 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. 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. deutetrabenazine and fluoxetine 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). olanzapine and deutetrabenazine both increase sedation. Use Caution/Monitor.dexchlorpheniramineMonitor Closely (1)dexchlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.dexfenfluramineMonitor Closely (3)fluoxetine will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. fluoxetine and dexfenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely. 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.Minor (1)dexmethylphenidate increases effects of fluoxetine by decreasing metabolism. Minor/Significance Unknown.dextroamphetamineMonitor Closely (3)fluoxetine and dextroamphetamine both increase serotonin levels. Modify Therapy/Monitor Closely. olanzapine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. fluoxetine will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.dextroamphetamine transdermalMonitor Closely (2)fluoxetine, dextroamphetamine transdermal. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and concomitant serotonergic drug(s). fluoxetine 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. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and CYP2D6 inhibitor.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).Serious - Use Alternative (2)fluoxetine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug. fluoxetine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.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 (2)fluoxetine will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. diazepam and olanzapine both increase sedation. Use Caution/Monitor.diazepam intranasalMonitor Closely (2)fluoxetine will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam. diazepam intranasal, fluoxetine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.dichlorphenamideMonitor Closely (1)dichlorphenamide and fluoxetine both decrease serum potassium. Use Caution/Monitor.diclofenacMonitor Closely (2)fluoxetine will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. fluoxetine, diclofenac. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.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 olanzapine both increase sedation. Use Caution/Monitor. difelikefalin and fluoxetine both increase sedation. Use Caution/Monitor.difenoxin hclMonitor Closely (1)difenoxin hcl and olanzapine both increase sedation. Use Caution/Monitor.diflunisalMonitor Closely (1)fluoxetine, diflunisal. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.dihydroergotamineMonitor Closely (2)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). fluoxetine and dihydroergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.dihydroergotamine intranasalMonitor Closely (1)fluoxetine and dihydroergotamine intranasal both increase serotonin levels. Modify Therapy/Monitor Closely.dimenhydrinateMonitor Closely (1)dimenhydrinate and olanzapine both increase sedation. Use Caution/Monitor.diphenhydramineMonitor Closely (4)diphenhydramine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor. diphenhydramine and olanzapine both increase sedation. Use Caution/Monitor. diphenhydramine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. olanzapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.Minor (1)diphenhydramine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.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 (2)olanzapine and disopyramide both increase QTc interval. Avoid or Use Alternate Drug. disopyramide and fluoxetine 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 (2)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. dofetilide and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.dolasetronMonitor Closely (2)dolasetron and fluoxetine both increase QTc interval. Use Caution/Monitor. dolasetron and olanzapine both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)dolasetron, fluoxetine. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.donepezilMonitor Closely (3)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 instances fluoxetine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. donepezil and fluoxetine both increase QTc interval. Use Caution/Monitor.dopamineMonitor 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.Serious - Use Alternative (1)fluoxetine and dosulepin both increase serotonin levels. Avoid or Use Alternate Drug.doxepinMonitor Closely (3)doxepin and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. olanzapine and doxepin both increase sedation. Use Caution/Monitor. 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 instancesSerious - Use Alternative (2)fluoxetine and doxepin both increase serotonin levels. Avoid or Use Alternate Drug. fluoxetine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.doxylamineMonitor Closely (1)doxylamine and olanzapine both increase sedation. Use Caution/Monitor.dronedaroneContraindicated (1)olanzapine and dronedarone both increase QTc interval. Contraindicated.Monitor Closely (1)dronedarone and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)dronedarone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.droperidolMonitor Closely (3)droperidol and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. 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.duloxetineSerious - Use Alternative (2)duloxetine and fluoxetine both increase serotonin levels. Avoid or Use Alternate Drug. fluoxetine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.Minor (1)duloxetine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.edoxabanMonitor Closely (1)fluoxetine increases effects of edoxaban by anticoagulation. Use Caution/Monitor. SSRIs may inhibit platelet aggregation, thus increase bleeding risk when coadministered with anticoagulants.efavirenzMonitor Closely (2)efavirenz and fluoxetine both increase QTc interval. Use Caution/Monitor. 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 (2)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). eletriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)fluoxetine, eletriptan. Mechanism: unknown. Minor/Significance Unknown. Risk of weakness, dyspnea, chest pain.eliglustatContraindicated (1)fluoxetine increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.Monitor Closely (1)eliglustat increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.Serious - Use Alternative (2)eliglustat and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. olanzapine and eliglustat both increase QTc interval. Avoid or Use Alternate Drug.eluxadolineMonitor Closely (1)fluoxetine increases levels of eluxadoline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2D6 inhibitors.elvitegravir/cobicistat/emtricitabine/tenofovir DFMonitor Closely (2)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events. elvitegravir/cobicistat/emtricitabine/tenofovir DF decreases levels of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Elvitegravir is a moderate CYP2C9 inducer.encainideMonitor Closely (1)fluoxetine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.encorafenibSerious - Use Alternative (2)encorafenib and fluoxetine both increase QTc interval. Avoid or Use Alternate Drug. Encorafenib is associated with dose-dependent QTc interval prolongation. Avoid with drugs known to prolong QT interval. encorafenib and olanzapine both increase QTc interval. Avoid or Use Alternate Drug. Limited data, including