What the FDA labels say about taking them together
Primidone and rufinamide
Rufinamide's FDA label of December 15, 2022 names primidone in its drug interactions section; the primidone label PlainMeds reads does not name rufinamide. The rufinamide label: “AED Co-administered: Primidone; Influence of Rufinamide on AED concentration a): Not Investigated; Influence of AED on Rufinamide concentration: Decrease by 25 to 46% c) ’ d) Independent of dose or concentration of …”
Check it at the source: the primidone FDA label on DailyMed (effective September 10, 2026, Bausch Health US, LLC); the rufinamide FDA label on DailyMed (effective December 15, 2022, Eisai Inc.).
What does the primidone label say about rufinamide?
Primidone's label (effective September 10, 2026) does not name rufinamide in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Mysoline), NDA009170 (Valeant), as published by Bausch Health US, LLC, effective September 10, 2026 (SPL set af593171-dabb-4ea3-b44c-89ed457b2c46), via openFDA; the full label on DailyMed
What does the rufinamide label say about primidone?
Rufinamide label, drug interactionsAED Co-administered: Primidone; Influence of Rufinamide on AED concentration a): Not Investigated; Influence of AED on Rufinamide concentration: Decrease by 25 to 46% c) ’ d) Independent of dose or concentration of primidone
Source: FDA drug label (Banzel), Eisai Inc., effective December 15, 2022 (SPL set 0a3fa925-1abd-458a-bd57-4ae780a1ef2d), 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
| Primidone | Rufinamide | |
|---|---|---|
| Labeled for | Seizures and epilepsy | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0914 per tablet 50 mg tablet | $0.203 per mL 40 mg/mL suspension |
| 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