What Is Zarontin? Uses, Dosage, and What You Need to Know in 2026

Zarontin is a medication many patients and families have never heard of until their neurologist prescribes it. If you or your child has recently been diagnosed with absence epilepsy, this guide will give you a clear, complete picture of what Zarontin is, how it works, and what to expect.

What Is Zarontin?

Zarontin is the brand name for ethosuximide, an anticonvulsant medication in the succinimide drug class. It has been FDA-approved since the 1960s and is used specifically to control absence seizures (also called petit mal seizures) in patients aged 3 and older.

Absence seizures are brief episodes—usually 5 to 30 seconds—characterized by a sudden lapse in consciousness and activity. The person appears to stare blankly, becomes momentarily unresponsive, and then resumes normal activity as if nothing happened. These seizures can occur dozens or even hundreds of times per day in untreated patients.

Who Makes Zarontin?

Brand-name Zarontin is manufactured by Pfizer (Parke-Davis division). Generic ethosuximide capsules are produced by several other pharmaceutical companies. Both forms are FDA-approved and therapeutically equivalent.

What Is Zarontin Used For?

Zarontin's sole FDA-approved indication is the control of absence (petit mal) epilepsy. It is the gold-standard, first-line treatment for this specific seizure type. A landmark randomized controlled trial published in the New England Journal of Medicine in 2010—the largest study ever conducted for childhood absence epilepsy—confirmed that ethosuximide achieves seizure freedom in approximately 45% of children at 12 months, with a superior tolerability profile compared to valproic acid.

It may also be used in combination with other anticonvulsants when other seizure types (such as generalized tonic-clonic seizures) coexist with absence seizures—but because ethosuximide only covers absence seizures, a second agent is needed to manage the other types.

What Forms Does Zarontin Come In?

Zarontin is available in two forms:

• 250 mg capsules — Soft gelatin capsules. Available as generic ethosuximide and formerly as brand Zarontin.
• 250 mg/5 mL oral solution — Raspberry-flavored liquid; manufactured by Pfizer as brand-name Zarontin. Each teaspoon (5 mL) contains 250 mg of ethosuximide. Useful for children who have difficulty swallowing capsules.

What Is the Typical Dosage of Zarontin?

Dosing is individualized by your neurologist based on your age, weight, and seizure response. General guidelines:

• Ages 3–6 years: Start at 250 mg (1 capsule or 1 teaspoon) per day
• Ages 6 and older / adults: Start at 500 mg (2 capsules) per day
• Titration: Dose is increased by 250 mg every 4–7 days until seizures are controlled with minimal side effects
• Optimal pediatric dose: 20 mg/kg/day for most pediatric patients
• Maximum dose: Typically 1,500 mg/day; doses above this should only be given under close medical supervision
• Therapeutic range: 40–100 μg/mL in serum; levels are sometimes checked via blood test

How Should I Take Zarontin?

• Take exactly as prescribed—do not change your dose without talking to your neurologist
• Can be taken with or without food; taking with food helps reduce stomach upset
• Take at the same time(s) each day for consistent drug levels
• If you miss a dose, take it as soon as you remember—unless it's almost time for the next dose
• Never stop abruptly — Sudden discontinuation can trigger absence status epilepticus. Always taper under medical guidance.

Is Zarontin a Controlled Substance?

No. Zarontin (ethosuximide) is not a controlled substance. There are no DEA scheduling requirements, no early refill restrictions, and no special prescription forms required. It can be prescribed by any licensed physician, nurse practitioner, or physician assistant with prescribing authority.

How Much Does Zarontin Cost?

Without insurance, Zarontin can cost $200–$580 per month. With GoodRx, generic ethosuximide can be as low as $33.61 per month. Most insurance plans cover generic ethosuximide with a $10–$50 copay. For a complete savings guide, see our post on how to save money on Zarontin in 2026.

Can Zarontin Be Hard to Find?

Yes—Zarontin is a niche medication that many pharmacies don't stock routinely. While there is no formal FDA shortage as of 2026, intermittent stocking issues are common. If your pharmacy doesn't have it, medfinder.com can call pharmacies near you to find which ones have it in stock.