What the FDA labels say about taking them together
Fluorouracil and irinotecan
Irinotecan's FDA label (Onivyde) of March 3, 2025 names fluorouracil in its boxed warning section; the fluorouracil labels PlainMeds reads (4) do not name irinotecan.
Check it at the source: the fluorouracil FDA label on DailyMed (effective January 19, 2026, Eugia US LLC); the irinotecan FDA label on DailyMed (effective May 12, 2026, Pharmacia & Upjohn Company LLC).
What does the fluorouracil label say about irinotecan?
Fluorouracil's label (effective January 19, 2026) and its 3 other brand-application labels do not name irinotecan in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (FLUOROURACIL), Eugia US LLC, effective January 19, 2026 (SPL set 697816ce-dc05-4943-b7f0-2f0b125e93b7), via openFDA; the full label on DailyMed
What does the irinotecan label say about fluorouracil?
Onivyde label (Ipsen Biopharmaceuticals, Inc., March 3, 2025), boxed warningSEVERE NEUTROPENIA AND SEVERE DIARRHEA Neutropenia Severe and life-threatening neutropenia, including fatal neutropenic sepsis and fatal neutropenic fever, has occurred in patients receiving ONIVYDE in combination with oxaliplatin, fluorouracil and leucovorin and in combination with fluorouracil and leucovorin.
Onivyde label (Ipsen Biopharmaceuticals, Inc., March 3, 2025), warnings and precautionsIn NAPOLI 3, Grade 3 and 4 neutropenia occurred in 26% of patients receiving ONIVYDE in combination with oxaliplatin, fluorouracil, and leucovorin (NALIRIFOX) and fatal neutropenic fever in 0.3% of patients [see Adverse Reactions (6.1) ].
Source: FDA drug label (Onivyde, NDA207793), Ipsen Biopharmaceuticals, Inc., effective March 3, 2025 (SPL set c8b58efa-1820-48a4-b70d-62918fc4abfc), via openFDA
Source: FDA drug label (Camptosar), NDA020571 (Pfizer Inc), as published by Pharmacia & Upjohn Company LLC, effective May 12, 2026 (SPL set e518dfc6-7e93-4fee-a66c-51e1ab71c056), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Fluorouracil | Irinotecan | |
|---|---|---|
| Labeled for | Colorectal cancer | Colorectal cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.616 per gram 5% cream | n/a |
| Shortage now | No current entry | A presentation being discontinued |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once