Prescription medicine
Primidone Brand names: Mysoline
Primidone (Mysoline) is a prescription medicine with an FDA approval on record since 1954. FDA's NDC Directory lists it from 21 generic labelers, and pharmacies paid $0.0914 per primidone 50 mg tablet in the October 7, 2026 NADAC survey.
- Generic listed
Check it at the source: the primidone FDA label on DailyMed (effective September 10, 2026, Bausch Health US, LLC); the NDA 9170 record on Drugs@FDA; every primidone label on DailyMed.
Highlights of the record
FDA label of September 10, 2026; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026; NADAC October 7, 2026
Used for
From the label: indications and usageMYSOLINE, used alone or concomitantly with other anticonvulsants, is indicated in the control of grand mal, psychomotor, and focal epileptic seizures.
Forms and strengths
- 50 mg
- 125 mg
- 250 mg
Tablet.
On the market
- Earliest approval on file
- March 8, 1954 Mysoline, Valeant; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- 10 first December 1, 1978; 7 with a marketed status in Drugs@FDA
- Labelers listed (NDC)
- 22 of which 21 under generic applications, 1 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- $0.0914 per tablet Primidone 50 mg tablet
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- 6 since 2026 0 Class I among all firms' recalls; latest June 3, 2026
- FAERS reports
- 10,126 through July 30, 2026
What is primidone used for?
From the label: indications and usageMYSOLINE, 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.
Conditions named in the indications of primidone's FDA labels, with every medicine labeled for each:
From other primidone labelsSeizures and epilepsy: INDICATIONS AND USAGE MYSOLINE, used alone or concomitantly with other anticonvulsants, is indicated in the control of grand mal, psychomotor, and focal epileptic seizures.
FDA pharmacologic class: Anti-epileptic Agent.
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 patient leaflet for primidone say first?
The FDA-approved Medication Guide or Patient Information that comes with the medicine, in its own words.
From the patient leaflet: What is the most important information I should know about MYSOLINE?Like other antiepileptic drugs, MYSOLINE may cause suicidal thoughts or actions in a very small number of people, about 1 in 500. Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you: • thoughts about suicide or dying • attempts to commit suicide • new or worsening depression • new or worsening anxiety • feeling agitated or restless • panic attacks • trouble sleeping (insomnia) • new or worsening irritability • acting aggressive, being angry, or violent • acting on dangerous impulses • an extreme increase in activity and talking (mania) • other unusual changes in behavior or mood Do not stop taking MYSOLINE without first talking to a healthcare provider. • Stopping MYSOLINE suddenly can cause serious problems. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus). Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes. How can I watch for early symptoms of suicidal thoughts and actions? • Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. • Keep all follow-up visits with your healthcare provider as scheduled. • Call your healthcare provider between visits as needed, especially if you are worried about symptoms.
From the patient leaflet: What should I avoid while taking MYSOLINE?MYSOLINE can make you sleepy or dizzy. Do not drink alcohol or take other drugs that make you sleepy or dizzy while taking MYSOLINE without first discussing this with your healthcare provider. Taking MYSOLINE with alcohol or drugs that cause sleepiness or dizziness may make your sleepiness or dizziness worse. • Do not drive, operate heavy machinery, or do other dangerous activities until you know how MYSOLINE affects you. MYSOLINE can slow your thinking and motor skills.
From the patient leaflet: How should I store MYSOLINE?Store MYSOLINE at room temperature between 68° to 77°F (20° to 25°C) in a tight, light-resistant container. Keep MYSOLINE and all medicines out of reach of children. General Information about MYSOLINE Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use MYSOLINE for a condition for which it was not prescribed. Do not give MYSOLINE to other people, even if they have the same symptoms that you have. It may harm them. This Medication Guide summarizes the most important information about MYSOLINE. If you would like more information, talk with your healthcare provider. You can ask your pharmacist or healthcare provider for information about MYSOLINE that is written for health professionals. For more information, go to www.bauschhealth.com or call 1-800-321-4576.
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
Is there a generic for primidone (Mysoline)?
The FDA approved the first generic primidone on December 1, 1978. 10 generic applications are approved; 7 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.
FDA's NDC Directory lists primidone from 21 labelers under a generic (ANDA) application and from 1 brand labeler. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.
- 1954 earliest approval on file
- 1978 first generic approved
- red ticks recalls
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What do pharmacies pay for primidone (Mysoline)?
In CMS's NADAC survey of October 7, 2026, pharmacies paid $0.0914 per Primidone 50 mg tablet, down 15% from $0.108 on October 8, 2025. The chart's scale runs from the lowest to the highest price shown, not from zero. NADAC is what retail pharmacies paid their wholesalers, per unit, in CMS's monthly survey; what a patient pays depends on insurance and the pharmacy.
- Primidone 50 mg tablet (generic)
| Strength and form | Brand or generic | Pharmacy cost | 30 tablets, or one pen or vial | 12-month change |
|---|---|---|---|---|
| Primidone 125 mg tablet | Generic | $1.38 per tablet | $41.36 | +5% |
| Primidone 250 mg tablet | Generic | $0.228 per tablet | $6.83 | -15% |
| Primidone 50 mg tablet | Generic | $0.0914 per tablet | $2.74 | -15% |
Source: CMS National Average Drug Acquisition Cost (NADAC) survey, October 7, 2026: what retail pharmacies paid per unit; not a counter price
Has primidone been recalled?
The FDA's Enforcement Report lists 6 recalls naming primidone since 2026: 0 Class I (the most serious), 0 Class II, 6 Class III; 6 still ongoing. A recall names products and lots, not every product of the medicine.
| Started | Class | Company | Reason |
|---|---|---|---|
| June 3, 2026 | Class III | Amneal Pharmaceuticals, LLC | Cross Contamination with Other Products: due to a potential for cross-contamination with Acemetacin API due to an issue at the API manufacturer. |
| May 1, 2026 | Class III | Amerisource Health Services LLC | Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. |
| April 27, 2026 | Class III | Golden State Medical Supply Inc. | Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. |
| April 24, 2026 | Class III | Lannett Company Inc. | Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. |
Source: FDA Enforcement Report (drug recalls) via openFDA, through October 8, 2026
What does the primidone label say about other medicines?
The primidone label names 1 other medicine in its interaction, contraindication or warning sections. The labels of 18 other medicines name primidone. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Phenobarbital | contraindications | CONTRAINDICATIONS Primidone is contraindicated in: 1) patients with porphyria and 2) patients who are hypersensitive to phenobarbital (see ACTIONS ). |
Other labels that name primidone
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 do FAERS reports show for primidone?
The FDA Adverse Event Reporting System holds 10,126 reports that list primidone among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 874 are coded as a death and 3,162 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What else is labeled for the same conditions as primidone?
20 other medicines are given the same way (oral) and in the same FDA class as primidone or labeled mainly for the same use (seizures and epilepsy), the same class first. Seizures and epilepsy lists all 27 medicines labeled for it, by any route. The first 8 are below. They are listed as records, not as substitutes: whether one can replace another is a prescriber's decision.
| Medicine | Shared indication | Generic labelers (oral) | Pharmacy cost | Shortage |
|---|---|---|---|---|
| Gabapentin | Seizures and epilepsy | 87 labelers | $0.0218 per capsule 100 mg capsule | No current entry |
| Lamotrigine | Seizures and epilepsy | 50 labelers | $0.0268 per tablet 25 mg tablet | A presentation being discontinued |
| Divalproex | Seizures and epilepsy | 44 labelers | $0.194 per tablet 500 mg tablet | No current entry |
| Oxcarbazepine | Seizures and epilepsy | 43 labelers | $0.167 per tablet 300 mg tablet | No current entry |
| Zonisamide | Seizures and epilepsy | 20 labelers | $0.106 per capsule 100 mg capsule | No current entry |
| Valproic acid | Seizures and epilepsy | 19 labelers | $0.243 per capsule 250 mg capsule | Listed; available |
| Phenytoin | Seizures and epilepsy | 23 labelers | $0.145 per capsule 100 mg capsule | No current entry |
| Felbamate | Seizures and epilepsy | 9 labelers | $1.00 per tablet 600 mg tablet | No current entry |
Source: FDA drug labels (indications), NDC Directory, NADAC of October 7, 2026, FDA shortages (October 8, 2026)
How does primidone compare with medicines for the same use?
1 side-by-side page set primidone beside a medicine whose label shares a use: approvals, generics, pharmacy cost, warnings and supply.
What next?
- Alternatives to primidone
- 20 medicines for the same use
- Other anti-seizure medicines
- the pharmacologic class, with prices and generics
- Primidone side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other