level or effect of fluoxetine by decreasing metabolism. Modify Therapy/Monitor Closely. Consider decreasing the dose of these drugs when given coadministered with methylphenidate. Monitor for drug toxiticities when initiating or discontinuing methylphenidate. methocarbamolmethocarbamol and olanzapine both increase sedation. Use Caution/Monitor.methscopolaminemethscopolamine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.methscopolamine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.olanzapine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.methylenedioxymethamphetamineolanzapine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methylergonovinemethylergonovine, 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).methylphenidateolanzapine increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.metoclopramideolanzapine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.mexiletinemexiletine will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.midazolammidazolam and olanzapine both increase sedation. Use Caution/Monitor.midazolam intranasalmidazolam intranasal, fluoxetine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.olanzapine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.fluoxetine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.midazolam intranasal, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.midodrineolanzapine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.mifepristonemifepristone, fluoxetine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.mifepristonemifepristone, olanzapine. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.miglitololanzapine, miglitol. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.milnacipranmilnacipran, 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).mipomersenmipomersen, fluoxetine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.mirabegronmirabegron will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapineolanzapine and mirtazapine both increase QTc interval. Use Caution/Monitor.fluoxetine and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.mirtazapine 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 instancesolanzapine and mirtazapine both increase sedation. Use Caution/Monitor.modafinilmodafinil will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.olanzapine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.morphinefluoxetine and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.morphinemorphine and olanzapine both increase sedation. Use Caution/Monitor.motherwortolanzapine and motherwort both increase sedation. Use Caution/Monitor.moxifloxacinfluoxetine and moxifloxacin both increase QTc interval. Modify Therapy/Monitor Closely.moxonidineolanzapine and moxonidine both increase sedation. Use Caution/Monitor.nabiloneolanzapine and nabilone both increase sedation. Use Caution/Monitor.nabumetonefluoxetine, nabumetone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.nalbuphinenalbuphine and olanzapine both increase sedation. Use Caution/Monitor.naproxenfluoxetine, naproxen. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.naratriptannaratriptan and fluoxetine both increase serotonin levels. Modify Therapy/Monitor Closely.naratriptan, 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).nateglinideolanzapine, nateglinide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.fluoxetine will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.nifedipinefluoxetine will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider initiating nifedipine at the lowest dose available if given concomitantly with this medicationnorepinephrineolanzapine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.nilotinibfluoxetine and nilotinib both increase QTc interval. Modify Therapy/Monitor Closely.nitisinonenitisinone will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Nitisinone inhibits CYP2C9. Caution if CYP2C9 substrate coadministered, particularly those with a narrow therapeutic index.nortriptylineolanzapine and nortriptyline both increase sedation. Use Caution/Monitor.olanzapine and nortriptyline both increase QTc interval. Use Caution/Monitor.nortriptyline and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely.octreotidefluoxetine and octreotide both increase QTc interval. Modify Therapy/Monitor Closely.ofloxacinolanzapine and ofloxacin both increase QTc interval. Use Caution/Monitor.octreotide (Antidote)fluoxetine and octreotide (Antidote) both increase QTc interval. Modify Therapy/Monitor Closely.ofloxacinfluoxetine and ofloxacin both increase QTc interval. Use Caution/Monitor.olanzapineolanzapine and fluoxetine both increase QTc interval. Use Caution/Monitor.oliceridinefluoxetine, oliceridine. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely.fluoxetine will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. oliceridine, olanzapine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. 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.olodaterol inhaledfluoxetine and olodaterol inhaled both increase QTc interval. Modify Therapy/Monitor Closely. Fluoxetine prolongs the QT interval; the prescribing information for fluoxetine recommends avoiding concurrent use of other drugs that may prolong the QT interval; risk may be increased with higher doses and/or when associated with hypokalemia; drugs that prolong the QTc interval may potentiate the effects of beta2 agonists on the cardiovascular systemonabotulinumtoxinAonabotulinumtoxinA decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.onabotulinumtoxinA decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.olanzapine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.opium tinctureopium tincture and olanzapine both increase sedation. Use Caution/Monitor.orphenadrineorphenadrine and olanzapine both increase sedation. Use Caution/Monitor.osilodrostatosilodrostat and olanzapine both increase QTc interval. Use Caution/Monitor.osilodrostat and fluoxetine both increase QTc interval. Use Caution/Monitor.osimertinibosimertinib and olanzapine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.osimertinib and fluoxetine both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.oxaliplatinoxaliplatin will increase the level or effect of olanzapine by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.oxaprozinfluoxetine, oxaprozin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.oxazepamoxazepam and olanzapine both increase sedation. Use Caution/Monitor.oxybutyninoxybutynin decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.oxybutynin decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.olanzapine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.oxybutynin topicaloxybutynin topical decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.oxybutynin topical decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.olanzapine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.oxybutynin transdermaloxybutynin transdermal decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.oxybutynin transdermal decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.olanzapine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.oxycodoneoxycodone and olanzapine both increase sedation. Use Caution/Monitor.oxymorphoneoxymorphone and olanzapine both increase sedation. Use Caution/Monitor.ozanimodozanimod and fluoxetine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.ozanimod and olanzapine both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.paliperidoneolanzapine and paliperidone both increase sedation. Use Caution/Monitor.fluoxetine and paliperidone both increase QTc interval. Use Caution/Monitor.olanzapine and paliperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.pancuroniumpancuronium decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.pancuronium decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.olanzapine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.parecoxibfluoxetine will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.fluoxetine, parecoxib. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.papaveretumpapaveretum and olanzapine both increase sedation. Use Caution/Monitor.papaverineolanzapine and papaverine both increase sedation. Use Caution/Monitor.paroxetineparoxetine, 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 paroxetine both increase QTc interval. Use Caution/Monitor.pasireotideolanzapine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.fluoxetine and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.peginterferon alfa 2apeginterferon alfa 2a will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.peginterferon alfa 2bpeginterferon alfa 2b, fluoxetine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.pentazocinepentazocine and olanzapine both increase sedation. Use Caution/Monitor.fluoxetine and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.pentobarbitalpentobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.pentobarbital and olanzapine both increase sedation. Use Caution/Monitor.pentoxifyllinepentoxifylline increases toxicity of fluoxetine by anticoagulation. Use Caution/Monitor. May increase bleeding.perhexilinefluoxetine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.perphenazineolanzapine and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.olanzapine and perphenazine both increase sedation. Use Caution/Monitor.olanzapine and perphenazine both increase QTc interval. Use Caution/Monitor.phendimetrazineolanzapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenelzinephenelzine, 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).phenobarbitalphenobarbital will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.phenobarbital and olanzapine both