Fluvoxamine and Olanzapine interaction
Fluvoxamine and Olanzapine: 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 Fluvoxamine (fluvoxamine maleate) label · effective 2026-04-23
CNS Active Drugs Antipsychotics: See Warnings and Precautions ( 5.2 ) .
From the Olanzapine (Zyprexa) label · effective 2026-02-11
Fluvoxamine: May increase olanzapine levels.
This results in a mean increase in olanzapine Cmax following fluvoxamine of 54% in female nonsmokers and 77% in male smokers.
Lower doses of olanzapine should be considered in patients receiving concomitant treatment with fluvoxamine.
Inhibitors of CYP1A2 Fluvoxamine: Fluvoxamine, a CYP1A2 inhibitor, decreases the clearance of olanzapine.
Effect of Olanzapine on Drug Metabolizing Enzymes — In vitro studies utilizing human liver microsomes suggest that olanzapine has little potential to inhibit CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A.
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.