What the FDA labels say about taking them together
Carbamazepine and primidone
Carbamazepine's FDA label of August 20, 2026 names primidone in its drug interactions section; the primidone label PlainMeds reads does not name carbamazepine. The carbamazepine label: “Clomipramine, P henytoin, and P rimidone EQUETRO can increase the concentrations of clomipramine, phenytoin, and primidone.”
Check it at the source: the carbamazepine FDA label on DailyMed (effective August 20, 2026, Novartis Pharmaceuticals Corporation); the primidone FDA label on DailyMed (effective September 10, 2026, Bausch Health US, LLC).
What does the carbamazepine label say about primidone?
Carbamazepine label, drug interactionsDrugs that have been shown, or that would be expected, to decrease plasma carbamazepine levels include cisplatin, doxorubicin HCl, felbamate, fosphenytoin, rifampin, phenobarbital, phenytoin, primidone, methsuximide, theophylline, aminophylline.
Carbamazepine label, warningsHypersensitivity Hypersensitivity reactions to carbamazepine have been reported in patients who previously experienced this reaction to anticonvulsants, including phenytoin, primidone, and phenobarbital.
Carbatrol label (Takeda Pharmaceuticals America, Inc., August 17, 2026), drug interactionsAminophylline, cisplatin, doxorubicin HCL, felbamate, fosphenytoin, methsuximide, phenobarbital, phenytoin (1), primidone, rifampin and theophylline. (1) Phenytoin plasma levels have also been reported to increase and decrease in the presence of carbamazepine, see below.
Equetro label (Validus Pharmaceuticals LLC, August 19, 2025), drug interactionsClomipramine, P henytoin, and P rimidone EQUETRO can increase the concentrations of clomipramine, phenytoin, and primidone.
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 primidone label say about carbamazepine?
Primidone's label (effective September 10, 2026) does 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 (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
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 | Primidone | |
|---|---|---|
| Labeled for | Bipolar disorder, Seizures and epilepsy | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.119 per tablet 200 mg tablet | $0.0914 per tablet 50 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