What the FDA labels say about taking them together
Fluorouracil and tinidazole
Tinidazole's FDA label of December 27, 2021 names fluorouracil in its drug interactions section; the fluorouracil labels PlainMeds reads (4) do not name tinidazole. The tinidazole label: “Monitor for toxicities of these immunosuppressive drugs Fluorouracil: Monitor for fluorouracil-associated toxicities Phenytoin, fosphenytoin:”
Check it at the source: the fluorouracil FDA label on DailyMed (effective January 19, 2026, Eugia US LLC); the tinidazole FDA label on DailyMed (effective December 27, 2021, Mission Pharmacal Company).
What does the fluorouracil label say about tinidazole?
Fluorouracil's label (effective January 19, 2026) and its 3 other brand-application labels do not name tinidazole 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 tinidazole label say about fluorouracil?
Tinidazole label, drug interactionsMonitor for toxicities of these immunosuppressive drugs ( 7.1 ) Fluorouracil: Monitor for fluorouracil-associated toxicities ( 7.1 ) Phenytoin, fosphenytoin:
Source: FDA drug label (Tindamax), Mission Pharmacal Company, effective December 27, 2021 (SPL set a0d01539-8413-4703-94cc-d221918630a1), 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 | Tinidazole | |
|---|---|---|
| Labeled for | Colorectal cancer | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.616 per gram 5% cream | $2.35 per tablet 500 mg tablet |
| 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