What the FDA labels say about taking them together
Cetuximab and fluorouracil
Cetuximab's FDA label of April 16, 2026 names fluorouracil in its boxed warning section; the fluorouracil labels PlainMeds reads (4) do not name cetuximab. The cetuximab label: “… radiation therapy or with a cetuximab product with platinum-based therapy and fluorouracil. Monitor serum electrolytes, including serum magnesium, potassium, and calcium, during and after ERBITUX administration.”
Check it at the source: the cetuximab FDA label on DailyMed (effective April 16, 2026, ImClone LLC); the fluorouracil FDA label on DailyMed (effective January 19, 2026, Eugia US LLC).
What does the cetuximab label say about fluorouracil?
Cetuximab label, boxed warningERBITUX can cause serious and fatal infusion reactions. ( 5.1 , 6 ) Immediately interrupt and permanently discontinue ERBITUX for serious infusion reactions. ( 2.5 ) Cardiopulmonary arrest or sudden death occurred in patients with squamous cell carcinoma of the head and neck receiving ERBITUX with radiation therapy or with a cetuximab product with platinum-based therapy and fluorouracil. Monitor serum electrolytes, including serum magnesium, potassium, and calcium, during and after ERBITUX administration.
Cetuximab label, warnings and precautionsIn EXTREME, where a cetuximab product was administered in combination with platinum-based therapy, the addition of cetuximab to cisplatin and fluorouracil resulted in an increased incidence of hypomagnesemia of any grade (14%) and of Grade 3 or 4 hypomagnesemia (7%).
Source: FDA drug label (ERBITUX), ImClone LLC, effective April 16, 2026 (SPL set 8bc6397e-4bd8-4d37-a007-a327e4da34d9), via openFDA; the full label on DailyMed
What does the fluorouracil label say about cetuximab?
Fluorouracil's label (effective January 19, 2026) and its 3 other brand-application labels do not name cetuximab 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
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
| Cetuximab | Fluorouracil | |
|---|---|---|
| Labeled for | Colorectal cancer | Colorectal cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $0.616 per gram 5% cream |
| Shortage now | No current entry | No current entry |
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