Methsuximide Brand names: Celontin

What is methsuximide used for?

From the label: indications and usage

Celontin is indicated for the control of absence (petit mal) seizures that are refractory to other drugs.

Conditions named in the indications of methsuximide's FDA labels, with every medicine labeled for each:

• Seizures and epilepsy

From other methsuximide labels

Seizures and epilepsy: INDICATIONS AND USAGE Celontin is indicated for the control of absence (petit mal) seizures that are refractory to other drugs.

FDA pharmacologic class: Anti-epileptic Agent.

What does the patient leaflet for methsuximide 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 CELONTIN?

Do not stop taking CELONTIN without first talking to your healthcare provider. Stopping CELONTIN suddenly can cause serious problems. CELONTIN can cause serious side effects, including: 1. Rare but serious blood problems that may be life-threatening. Call your healthcare provider right away if you have: o fever, swollen glands, or sore throat that come and go or do not go away o frequent infections or an infection that does not go away o easy bruising o red or purple spots on your body o bleeding gums or nose bleeds o severe fatigue or weakness 2. Systematic Lupus Erythematosus. Call your healthcare provider right away if you have any of these symptoms: o joint pain and swelling o muscle pain o fatigue o low-grade fever o pain in the chest that is worse with breathing o unexplained skin rash 3. Like other antiepileptic drugs, CELONTIN 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: o thoughts about suicide or dying o attempts to commit suicide o new or worse depression o new or worse anxiety o feeling agitated or restless o panic attacks o trouble sleeping (insomnia) o new or worse irritability o acting aggressive, being angry, or violent o acting on dangerous impulses o an extreme increase in activity and talking (mania) o other unusual changes in behavior or mood How can I watch for early symptoms of suicidal thoughts and actions? o Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. o 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 CELONTIN?

Do not drink alcohol or take other medicines that make you sleepy or dizzy while taking CELONTIN without first discussing this with your healthcare provider. CELONTIN taken with alcohol or medicines 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 CELONTIN affects you. CELONTIN can slow your thinking and motor skills.

From the patient leaflet: How should I store CELONTIN?

Store CELONTIN at room temperature, between 59°F to 86°F (15°C to 30°C). • Keep CELONTIN capsules in a dry place. • Keep CELONTIN out of the light. • Protect CELONTIN from heat. • Do not use CELONTIN capsules that if they do not look full or if the contents have melted. Keep CELONTIN and all medicines out of the reach of children.

Is there a generic for methsuximide (Celontin)?

The FDA approved the first generic methsuximide on May 1, 2023. 1 generic application is approved; 1 of it carries 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 methsuximide from 1 labeler 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. In the latest NADAC survey pharmacies bought only the brand, so a generic may not be on sale yet.

What do pharmacies pay for methsuximide (Celontin)?

In CMS's NADAC survey of October 7, 2026, pharmacies paid $4.40 per Celontin 300 mg capsule, about the same as a year earlier. 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.

What does the methsuximide label say about other medicines?

The methsuximide label names 2 other medicines in its interaction, contraindication or warning sections. The labels of 3 other medicines name methsuximide. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.

Other labels that name methsuximide

• Carbamazepine

Check methsuximide against other medicines

What do FAERS reports show for methsuximide?

The FDA Adverse Event Reporting System holds 181 reports that list methsuximide among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 2 are coded as a death and 39 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.

The most reported reactions

• Drug Ineffective (a use or a product term, not a reaction)25
• Seizure (a use or a product term, not a reaction)21
• Convulsion14
• Dizziness (named in the label)13
• Somnolence13
• Feeling Abnormal11
• Generalised Tonic-Clonic Seizure11
• Off Label Use (a use or a product term, not a reaction)11

Side effects: the label's list and every FAERS reaction

What else is labeled for the same conditions as methsuximide?

20 other medicines are given the same way (oral) and in the same FDA class as methsuximide 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.

Every medicine labeled for the same conditions as methsuximide

What next?

Alternatives to methsuximide

20 medicines for the same use

Other anti-seizure medicines

the pharmacologic class, with prices and generics

Methsuximide side effects

the label's list beside FAERS reports

Check an interaction

what two or more labels say about each other