Drug interactions
Fluvoxamine + Olanzapine
Severity: Moderate
Fluvoxamine and Olanzapine: moderate interaction.
Last updated
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.
Summary
Fluvoxamine strongly inhibits CYP1A2, the main route of olanzapine clearance, and can substantially raise olanzapine levels, causing sedation, orthostasis and metabolic or anticholinergic effects. A minor additive QT effect has also been suggested.
What this interaction means in plain words
Fluvoxamine and Olanzapine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Fluvoxamine belongs to Central Nervous System; Olanzapine belongs to Central Nervous System.
Why it happens
CYP1A2 inhibition by fluvoxamine reduces olanzapine clearance.
What to do
Start olanzapine at a lower dose, such as a reduced starting dose, and titrate by response and tolerability. Reduce the olanzapine dose when fluvoxamine is added.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Fluvoxamine
- Agomelatine + Fluvoxamine Contraindicated
- Alosetron + Fluvoxamine Contraindicated
- Fezolinetant + Fluvoxamine Contraindicated
- Fluvoxamine + Isocarboxazid Contraindicated
- Fluvoxamine + Mavacamten Contraindicated
- Fluvoxamine + Methylene blue Contraindicated
Other interactions of Olanzapine
Frequently asked questions
Can I take Fluvoxamine with Olanzapine?
MediHelp rates the interaction as moderate. Fluvoxamine and Olanzapine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Fluvoxamine strongly inhibits CYP1A2, the main route of olanzapine clearance, and can substantially raise olanzapine levels, causing sedation, orthostasis and metabolic or anticholinergic effects. A minor additive QT effect has also been suggested.
How serious is the interaction between Fluvoxamine and Olanzapine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start olanzapine at a lower dose, such as a reduced starting dose, and titrate by response and tolerability. Reduce the olanzapine dose when fluvoxamine is added.
What other medicines interact with Fluvoxamine?
MediHelp also lists interactions of Fluvoxamine with, for example, Agomelatine, Alosetron, Fezolinetant. The full list is on the Fluvoxamine page.
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