Drug interactions
Fluoxetine + Olanzapine
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Overview
Fluoxetine modestly increases olanzapine exposure via CYP2D6 inhibition, which may enhance olanzapine adverse effects.
Mechanism of action
Pharmacokinetic: CYP2D6 inhibition by fluoxetine/norfluoxetine increases olanzapine concentrations.
Clinical management
Monitor for increased olanzapine effects (sedation, orthostasis, EPS, metabolic changes); adjust olanzapine dose if clinically indicated, especially in elderly or hepatic impairment.
Drug reference
References
- SYMBYAX (olanzapine and fluoxetine) Prescribing Information — FDA Label
- Zyprexa (olanzapine) Prescribing Information — FDA Label
- Prozac (fluoxetine) Prescribing Information — FDA Label
Frequently asked questions
Can I take Fluoxetine with Olanzapine?
The interaction is rated: Moderate. Fluoxetine modestly increases olanzapine exposure via CYP2D6 inhibition, which may enhance olanzapine adverse effects.
How serious is the interaction between Fluoxetine and Olanzapine?
The interaction is rated: Moderate. Evidence level: High.
How is the interaction between Fluoxetine and Olanzapine managed?
Monitor for increased olanzapine effects (sedation, orthostasis, EPS, metabolic changes); adjust olanzapine dose if clinically indicated, especially in elderly or hepatic impairment.
Why do Fluoxetine and Olanzapine interact?
Pharmacokinetic: CYP2D6 inhibition by fluoxetine/norfluoxetine increases olanzapine concentrations.
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