What the FDA labels say about taking them together
Carbamazepine and metronidazole
Metronidazole's FDA label (Metronidazole) of June 12, 2025 names carbamazepine in its drug interactions section; the carbamazepine labels PlainMeds reads (3) do not name metronidazole. The metronidazole label: “Cytochrome P450 3A4 (CYP3A4) substrates Concomitant use of Metronidazole Injection and CYP3A4 substrates may increase respective CYP3A4-substrate plasma levels.”
Check it at the source: the carbamazepine FDA label on DailyMed (effective August 20, 2026, Novartis Pharmaceuticals Corporation); the metronidazole FDA label on DailyMed (effective September 3, 2024, Aurobindo Pharma Limited).
What does the carbamazepine label say about metronidazole?
Carbamazepine's label (effective August 20, 2026) and its 2 other brand-application labels do not name metronidazole in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Tegretol), Novartis Pharmaceuticals Corporation, effective August 20, 2026 (SPL set 8d409411-aa9f-4f3a-a52c-fbcb0c3ec053), via openFDA; the full label on DailyMed
What does the metronidazole label say about carbamazepine?
Metronidazole label (Baxter Healthcare Corporation, June 12, 2025), drug interactionsCytochrome P450 3A4 (CYP3A4) substrates Concomitant use of Metronidazole Injection and CYP3A4 substrates (e.g., amiodarone, tacrolimus, cyclosporine, carbamazepine, phenytoin, and quinidine) may increase respective CYP3A4-substrate plasma levels.
Source: FDA drug label (Metronidazole, NDA018657), Baxter Healthcare Corporation, effective June 12, 2025 (SPL set d2112f37-5080-4a19-bcc3-6386b49abe1d), via openFDA
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
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
| Carbamazepine | Metronidazole | |
|---|---|---|
| Labeled for | Bipolar disorder, Seizures and epilepsy | Bacterial infections |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.119 per tablet 200 mg tablet | $0.102 per tablet 250 mg tablet |
| Shortage now | A presentation being discontinued | In shortage |
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