What the FDA labels say about taking them together
Metronidazole and tinidazole
Tinidazole's FDA label of December 27, 2021 names metronidazole in its boxed warning section; the metronidazole labels PlainMeds reads (4) do not name tinidazole. The tinidazole label: “POTENTIAL RISK FOR CARCINOGENICITY Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent.”
Check it at the source: the metronidazole FDA label on DailyMed (effective September 3, 2024, Aurobindo Pharma Limited); the tinidazole FDA label on DailyMed (effective December 27, 2021, Mission Pharmacal Company).
What does the metronidazole label say about tinidazole?
Metronidazole's label (effective September 3, 2024) 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 (Metronidazole), Aurobindo Pharma Limited, effective September 3, 2024 (SPL set f68397ee-67db-472e-8607-4300064e37df), via openFDA; the full label on DailyMed
What does the tinidazole label say about metronidazole?
Tinidazole label, boxed warningPOTENTIAL RISK FOR CARCINOGENICITY Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent ( 13.1 ).
Tinidazole label, contraindicationsSevere irreversible hepatotoxicity/acute liver failure with fatal outcomes have been reported after initiation of metronidazole, another nitroimidazole drug, structurally related to tinidazole, in patients with Cockayne syndrome [see Adverse Reactions (6.2)] Prior history of hypersensitivity to tinidazole or other nitroimidazole derivatives (4, 6.1, 6.2) Patients with Cockayne syndrome
Tinidazole label, drug interactionsThe following drug interactions were reported for metronidazole, a chemically-related nitroimidazole and may therefore occur with tinidazole:
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
| Metronidazole | Tinidazole | |
|---|---|---|
| Labeled for | Bacterial infections | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.102 per tablet 250 mg tablet | $2.35 per tablet 500 mg tablet |
| Shortage now | In shortage | 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