Drug interactions
Olanzapine + Rifampin
Severity: Moderate
Olanzapine and Rifampin: 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
Rifampin is a potent enzyme inducer and can substantially lower olanzapine concentrations. This may lead to loss of antipsychotic control and relapse.
What this interaction means in plain words
Olanzapine and Rifampin 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.
Why it happens
Induction of CYP1A2 and glucuronidation enzymes by rifampin increases olanzapine clearance.
What to do
Monitor psychiatric response and consider increasing the olanzapine dose, guided by serum levels where available. Reduce the dose again after rifampin is discontinued.
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 Olanzapine
Frequently asked questions
Can I take Olanzapine with Rifampin?
MediHelp rates the interaction as moderate. Olanzapine and Rifampin 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. Rifampin is a potent enzyme inducer and can substantially lower olanzapine concentrations. This may lead to loss of antipsychotic control and relapse.
How serious is the interaction between Olanzapine and Rifampin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor psychiatric response and consider increasing the olanzapine dose, guided by serum levels where available. Reduce the dose again after rifampin is discontinued.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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