What the FDA labels say about taking them together
Cimetidine and tinidazole
Tinidazole's FDA label of December 27, 2021 names cimetidine in its drug interactions section; the cimetidine label PlainMeds reads does not name tinidazole. The tinidazole label: “Simultaneous administration of drugs that inhibit the activity of liver microsomal enzymes, i.e., CYP3A4 inhibitors such as cimetidine and ketoconazole, may prolong the half-life and decrease the plasma clearance of …”
Check it at the source: the cimetidine FDA label on DailyMed (effective July 15, 2026, Mylan Pharmaceuticals Inc.); the tinidazole FDA label on DailyMed (effective December 27, 2021, Mission Pharmacal Company).
What does the cimetidine label say about tinidazole?
Cimetidine's label (effective July 15, 2026) does 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 (Cimetidine), Mylan Pharmaceuticals Inc., effective July 15, 2026 (SPL set 06c0a509-026f-44e0-9975-a94a8de51d43), via openFDA; the full label on DailyMed
What does the tinidazole label say about cimetidine?
Tinidazole label, drug interactionsSimultaneous administration of drugs that inhibit the activity of liver microsomal enzymes, i.e., CYP3A4 inhibitors such as cimetidine and ketoconazole, may prolong the half-life and decrease the plasma clearance of tinidazole, increasing the plasma concentrations of 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
| Cimetidine | Tinidazole | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.236 per tablet 300 mg tablet | $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