Does Irinotecan Hydrochloride Interact with Fluorouracil?
Irinotecan Hydrochloride and Fluorouracil have a moderate drug interaction according to U.S. FDA drug labeling data. Co-administration reduces SN-38 Cmax by 14% and AUC by 8%. This sequence is used in combination trials and is recommended. The mechanism involves reduced active metabolite exposure when irinotecan followed by 5-fu and leucovorin. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Moderate
- Fluorouracil Class
- Nucleoside Metabolic Inhibitor
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Irinotecan Hydrochloride and Fluorouracil occurs because reduced active metabolite exposure when irinotecan followed by 5-fu and leucovorin. Clinically, this means co-administration reduces sn-38 cmax by 14% and auc by 8%. this sequence is used in combination trials and is recommended. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.
What To Tell Your Doctor or Pharmacist
If you are taking Irinotecan Hydrochloride and your doctor is considering prescribing Fluorouracil (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider