Drug interactions
Irinotecan + Isoniazid
Severity: Moderate
Irinotecan and Isoniazid: 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
Irinotecan is activated and also inactivated through CYP3A4 oxidation. Isoniazid may alter the balance, which could increase toxicity such as diarrhea and neutropenia, though the clinical importance is uncertain.
What this interaction means in plain words
Irinotecan and Isoniazid 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; Isoniazid belongs to Anti Bacterial.
Why it happens
CYP3A4 inhibition by isoniazid alters irinotecan metabolism.
What to do
Monitor for severe diarrhea and neutropenia and check blood counts regularly during treatment.
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 Isoniazid
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
Frequently asked questions
Can I take Irinotecan with Isoniazid?
MediHelp rates the interaction as moderate. Irinotecan and Isoniazid 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 is activated and also inactivated through CYP3A4 oxidation. Isoniazid may alter the balance, which could increase toxicity such as diarrhea and neutropenia, though the clinical importance is uncertain.
How serious is the interaction between Irinotecan and Isoniazid?
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 for severe diarrhea and neutropenia and check blood counts regularly during treatment.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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