Olanzapine and Olanzapine and fluoxetine interaction
Olanzapine and Olanzapine and fluoxetine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Olanzapine (Zyprexa) label · effective 2026-02-11
Potential for Other Drugs to Affect Olanzapine Diazepam — The co-administration of diazepam with olanzapine potentiated the orthostatic hypotension observed with olanzapine [see Drug Interactions ( 7.2 )] .
Lithium — Multiple doses of olanzapine (10 mg for 8 days) did not influence the kinetics of lithium.
Alcohol — Multiple doses of olanzapine did not influence the kinetics of ethanol [see Drug Interactions ( 7.1 )] .
Biperiden — Multiple doses of olanzapine did not influence the kinetics of biperiden.
Anticholinergic (antimuscarinic) Effects: Use with caution with other anticholinergic drugs and in patients with urinary retention, prostatic hypertrophy, constipation, paralytic ileus or related conditions.
From the Olanzapine and fluoxetine label · effective 2026-03-31
Potential for Other Drugs to Affect Olanzapine and Fluoxetine Capsules Benzodiazepines — Co-administration of diazepam with olanzapine potentiated the orthostatic hypotension observed with olanzapine [see Drug Interactions ( 7.7 )] .
The Effect of Other Drugs on Olanzapine — Fluoxetine, an inhibitor of CYP2D6, decreases olanzapine clearance a small amount [see Clinical Pharmacology ( 12.3 )].
Benzodiazepines — Multiple doses of olanzapine did not influence the pharmacokinetics of diazepam and its active metabolite N-desmethyldiazepam.
Lithium — Multiple doses of olanzapine did not influence the pharmacokinetics of lithium.
Biperiden — Multiple doses of olanzapine did not influence the pharmacokinetics of biperiden.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.