Drug interactions
Clozapine + Rifampin
Severity: Major
Clozapine and Rifampin: major interaction.
Last updated Sources: US FDA label
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 induces hepatic CYP enzymes that metabolize clozapine, lowering its plasma concentrations. This can lead to loss of antipsychotic control and relapse of psychosis.
What this interaction means in plain words
Clozapine and Rifampin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Induction of CYP1A2 and CYP3A4 by rifampin, increasing clozapine clearance.
What to do
Monitor clozapine plasma levels and psychiatric status, and increase the dose if needed. Reduce the dose again, with level monitoring, after rifampin is stopped to avoid toxicity.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Rifampin?
MediHelp rates the interaction as major. Clozapine and Rifampin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Rifampin induces hepatic CYP enzymes that metabolize clozapine, lowering its plasma concentrations. This can lead to loss of antipsychotic control and relapse of psychosis.
How serious is the interaction between Clozapine and Rifampin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor clozapine plasma levels and psychiatric status, and increase the dose if needed. Reduce the dose again, with level monitoring, after rifampin is stopped to avoid toxicity.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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