What the FDA labels say about taking them together
Carbamazepine and oxybutynin
Carbamazepine's FDA label of August 20, 2026 names oxybutynin in its drug interactions section; the oxybutynin labels PlainMeds reads (2) do not name carbamazepine. The carbamazepine label: “… danazol, diltiazem, macrolides, fluoxetine, fluvoxamine, trazodone, omeprazole, oxybutynin, isoniazid, niacinamide (nicotinamide), azoles, acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors.”
Check it at the source: the carbamazepine FDA label on DailyMed (effective August 20, 2026, Novartis Pharmaceuticals Corporation); the oxybutynin FDA label on DailyMed (effective December 16, 2025, Accord Healthcare, Inc.).
What does the carbamazepine label say about oxybutynin?
Carbamazepine label, drug interactionsDrugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides (e.g., erythromycin, clarithromycin), fluoxetine, fluvoxamine, trazodone, omeprazole, oxybutynin, isoniazid, niacinamide (nicotinamide), azoles (e.g., ketaconazole, itraconazole, fluconazole, voriconazole), acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors.
Carbatrol label (Takeda Pharmaceuticals America, Inc., August 17, 2026), drug interactionsAcetazolamide, aprepitant, azole antifungals (e.g., ketoconazole, itraconazole, fluconazole, voriconazole), cimetidine, ciprofloxacin, clarithromycin, dalfopristin, danazol, dantrolene, delavirdine, diltiazem, erythromycin, fluoxetine, fluvoxamine, grapefruit juice, ibuprofen, isoniazid, loratadine, macrolides, nefazodone, niacinamide, nicotinamide, olanzapine, omeprazole, oxybutynin, protease inhibitors, propoxyphene, quinine, quinupristin, ticlopidine, troleandomycin, valproate, verapamil, zileuton.
Equetro label (Validus Pharmaceuticals LLC, August 19, 2025), drug interactionsThe following drugs are CYP3A4 inhibitors: Acetazolamide, aprepitant, azole antifungals (e.g., ketoconazole, itraconazole, fluconazole, voriconazole ), cimetidine, ciprofloxacin, clarithromycin, dalfopristin, danazol, dantrolene, delavirdine, diltiazem, erythromycin, fluoxetine, fluvoxamine, grapefruit juice, ibuprofen, isoniazid, loratadine, nefazodone, niacinamide, nicotinamide, olanzapine, omeprazole, oxybutynin, quinine, quinupristin, ticlopidine, troleandomycin, valproate, verapamil, zileuton.
Source: FDA drug label (Carbatrol, NDA020712), Takeda Pharmaceuticals America, Inc., effective August 17, 2026 (SPL set bc03e499-5bac-4293-bff4-6864153a624d), via openFDA
Source: FDA drug label (Equetro, NDA021710), Validus Pharmaceuticals LLC, effective August 19, 2025 (SPL set be478f3c-40f6-47cc-8ab9-f420a9372b1c), via openFDA
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 oxybutynin label say about carbamazepine?
Oxybutynin's label (effective December 16, 2025) and its 1 other brand-application label do not name carbamazepine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (oxybutynin chloride), Accord Healthcare, Inc., effective December 16, 2025 (SPL set 61496a1e-17bf-4f45-a20c-5bb98fe545ee), 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 | Oxybutynin | |
|---|---|---|
| Labeled for | Bipolar disorder, Seizures and epilepsy | Overactive bladder |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.119 per tablet 200 mg tablet | $0.048 per tablet 5 mg tablet |
| Shortage now | A presentation being discontinued | 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