What the FDA labels say about taking them together
Carbamazepine and istradefylline
Istradefylline's FDA label of May 20, 2025 names carbamazepine in its drug interactions section; the carbamazepine labels PlainMeds reads (3) do not name istradefylline. The istradefylline label: “Therefore, it is recommended to avoid use of NOURIANZ with strong CYP3A4 inducers.”
Check it at the source: the carbamazepine FDA label on DailyMed (effective August 20, 2026, Novartis Pharmaceuticals Corporation); the istradefylline FDA label on DailyMed (effective May 20, 2025, Kyowa Kirin, Inc.).
What does the carbamazepine label say about istradefylline?
Carbamazepine's label (effective August 20, 2026) and its 2 other brand-application labels do not name istradefylline 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 istradefylline label say about carbamazepine?
Istradefylline label, drug interactionsTherefore, it is recommended to avoid use of NOURIANZ with strong CYP3A4 inducers (e.g., carbamazepine, rifampin, phenytoin, St. John's wort) [see Dosage and Administration (2.3) ].
Source: FDA drug label (NOURIANZ), Kyowa Kirin, Inc., effective May 20, 2025 (SPL set a7d008cb-b273-4049-a5d2-9c6902910d58), 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 | Istradefylline | |
|---|---|---|
| Labeled for | Bipolar disorder, Seizures and epilepsy | Parkinson's disease |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.119 per tablet 200 mg tablet | n/a |
| 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