Drug interactions
Fostamatinib + Irinotecan
Severity: Moderate
Fostamatinib and Irinotecan: 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
Fostamatinib's active metabolite R406 inhibits P-glycoprotein and may increase exposure to irinotecan and SN-38, which are P-gp substrates. This could intensify myelosuppression and diarrhea. Clinical data on this pair are lacking.
What this interaction means in plain words
Fostamatinib and Irinotecan 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.
Fostamatinib belongs to Oncology; Irinotecan belongs to Oncology.
Why it happens
R406 inhibits intestinal and other P-gp efflux, increasing substrate absorption and exposure.
What to do
Monitor blood counts and gastrointestinal toxicity, and reduce the irinotecan dose if toxicity occurs.
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 Fostamatinib
- Colchicine + Fostamatinib Major
- Fostamatinib + Phenytoin Major
- Amobarbital + Fostamatinib Moderate
- Apalutamide + Fostamatinib Moderate
- Atorvastatin + Fostamatinib Moderate
- Bosentan + Fostamatinib Moderate
Frequently asked questions
Can I take Fostamatinib with Irinotecan?
MediHelp rates the interaction as moderate. Fostamatinib and Irinotecan 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. Fostamatinib's active metabolite R406 inhibits P-glycoprotein and may increase exposure to irinotecan and SN-38, which are P-gp substrates. This could intensify myelosuppression and diarrhea. Clinical data on this pair are lacking.
How serious is the interaction between Fostamatinib and Irinotecan?
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 blood counts and gastrointestinal toxicity, and reduce the irinotecan dose if toxicity occurs.
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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