Drug interactions
Irinotecan + Rifabutin
Severity: Moderate
Irinotecan and Rifabutin: 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
Rifabutin induces CYP3A4 and may lower exposure to irinotecan and SN-38. This may reduce effectiveness of chemotherapy, although rifabutin is a weaker inducer than rifampicin.
What this interaction means in plain words
Irinotecan and Rifabutin 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.
Irinotecan belongs to Oncology; Rifabutin belongs to Anti Bacterial.
Why it happens
Rifabutin induces CYP3A4, increasing metabolic clearance of irinotecan and its active metabolite.
What to do
Use a non-inducing alternative antimycobacterial where possible. If it is unavoidable, monitor clinical response and toxicity.
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 Irinotecan
- Clozapine + Irinotecan Contraindicated
- Irinotecan + Sacituzumab govitecan Contraindicated
- Adenovirus types 4 and 7 live + Irinotecan Major
- Apalutamide + Irinotecan Major
- Atazanavir + Irinotecan Major
- Carbamazepine + Irinotecan Major
Other interactions of Rifabutin
- Cabotegravir + Rifabutin Contraindicated
- Lorlatinib + Rifabutin Contraindicated
- Rifabutin + Voriconazole Contraindicated
- Apixaban + Rifabutin Major
- Axitinib + Rifabutin Major
- Brexpiprazole + Rifabutin Major
Frequently asked questions
Can I take Irinotecan with Rifabutin?
MediHelp rates the interaction as moderate. Irinotecan and Rifabutin 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. Rifabutin induces CYP3A4 and may lower exposure to irinotecan and SN-38. This may reduce effectiveness of chemotherapy, although rifabutin is a weaker inducer than rifampicin.
How serious is the interaction between Irinotecan and Rifabutin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a non-inducing alternative antimycobacterial where possible. If it is unavoidable, monitor clinical response and toxicity.
What other medicines interact with Irinotecan?
MediHelp also lists interactions of Irinotecan with, for example, Clozapine, Sacituzumab govitecan, Adenovirus types 4 and 7 live. The full list is on the Irinotecan page.
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