Two medicines, side by side
Primidone vs gabapentin
Primidone and gabapentin are both labeled for seizures and epilepsy. Drugs@FDA records approvals of primidone since 1954 and of gabapentin since 1993. Pharmacies paid $0.0914 per primidone 50 mg tablet and $0.0218 per gabapentin 100 mg capsule (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. How each works, in its label's words: Primidone, “ACTIONS MYSOLINE raises electro- or chemoshock seizure thresholds or alters seizure patterns in experimental animals.”; Gabapentin, “The precise mechanisms by which gabapentin produces its analgesic and antiepileptic actions are unknown.”
Check it at the source: the primidone FDA label on DailyMed (effective September 10, 2026); the gabapentin FDA label on DailyMed (effective May 12, 2026).
Highlights of the primidone record
Primidone (Mysoline) · label of September 10, 2026
Used for
From the label: indicationsMYSOLINE, used alone or concomitantly with other anticonvulsants, is indicated in the control of grand mal, psychomotor, and focal epileptic seizures. It may control grand mal seizures refractory to other anticonvulsant therapy.
On the market
- Earliest approval on file
- March 8, 1954
- Generic labelers
- 21 labelers
- Pharmacy cost
- $0.0914 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 6
Highlights of the gabapentin record
Gabapentin (Neurontin) · label of May 12, 2026
Used for
From the label: indicationsNEURONTIN ® is indicated for: • Management of postherpetic neuralgia in adults • Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy NEURONTIN is indicated for: • Postherpetic neuralgia in adults ( 1 ) • Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy […]
On the market
- Earliest approval on file
- December 30, 1993
- Generic labelers
- 85 labelers
- Pharmacy cost
- $0.0218 per capsule
Supply and safety
- Shortage
- No current entry
- Recalls
- 22
Source: FDA drug labels via openFDA (Primidone label of September 10, 2026, Gabapentin label of May 12, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do primidone and gabapentin differ on the record?
How each works, in its label's words: Primidone, “ACTIONS MYSOLINE raises electro- or chemoshock seizure thresholds or alters seizure patterns in experimental animals.”; Gabapentin, “The precise mechanisms by which gabapentin produces its analgesic and antiepileptic actions are unknown.”
Both are in FDA's class anti-epileptic agents.
Generics: primidone since 1978; gabapentin since 2003 (Drugs@FDA).
| Primidone | Gabapentin | |
|---|---|---|
| Labeled for | Seizures and epilepsy | Nerve pain and fibromyalgia, Seizures and epilepsy |
| Pharmacologic class | Anti-epileptic Agent | Anti-epileptic Agent |
| How it works (label) | ACTIONS MYSOLINE raises electro- or chemoshock seizure thresholds or alters seizure patterns in experimental animals. The mechanism(s) of primidone’s antiepileptic action is not known. | The precise mechanisms by which gabapentin produces its analgesic and antiepileptic actions are unknown. |
| Half-life (label) | n/a | Gabapentin elimination half-life is 5 to 7 hours and is unaltered by dose or following multiple dosing. |
| Earliest approval on file (Drugs@FDA) | March 8, 1954 | December 30, 1993 |
| First generic approved | December 1, 1978 | September 12, 2003 |
| Generic labelers (NDC) | 21 labelers | 85 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.0914 per tablet (Primidone 50 mg tablet) | $0.0218 per capsule (Gabapentin 100 mg capsule) |
| 12-month price change | -15% | +0.9% |
| Boxed warning | No | No |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 6 | 22 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 10,126 | 362,654 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What next?
- Alternatives to primidone
- every medicine labeled for the same conditions