Generic Name: Ethosuximide


Treatment of absence (petit mal) seizures

250 mg capsule

How it Works

Zarontin® suppresses the 3 cycle per second spike & wave pattern that is the hallmark of the absence seizures. Most EEGs become normal while the patient is on the Zarontin®. It is well absorbed when taken by mouth, does not bind significantly to proteins and is broken down primarily by the liver. The half life is > 24 hours, in both children and adults.

Forms of the Medicine

  • Gel caps with 250 mg per capsule
  • Syrup with 250 mg /5 ml (teaspoon)


Zarontin® is given by mouth. Since the half life is long, it may be given once/day if tolerated by the patient. Otherwise, it should be given 2-3 times /day, and with food. Dosing amounts and frequency of dosing will be decided by the treating physician. In children, starting and maintenance doses are usually based on weight. Children over the age of 6 years and adults will usually start with about 500 mg per day. Some will require more.


Patients with simple absence epilepsy respond well to the Zarontin® after 12-24 months of treatment.

Side Effects

The most common side effects include those to the gastrointestinal system with stomachaches, cramps, nausea, vomiting and appetite changes. Other side effects may be hiccups, drowsiness, fatigue, dizziness, problems sleeping and behavioral changes. Allergic reactions may also occur and include rashes, systemic lupus erythematosis. Abnormalities may occur in the blood forming system with low white cell counts and bone marrow suppression.

Information for Pregnant Women and Nursing Mothers

Safety in pregnancy has not been established. It is known that women taking antiepileptic drugs have a higher incidence of birth defects than women who are not. Zarontin® is excreted in breast milk.

Drug Interactions

Zarontin® may increase Dilantin® levels. Depakote® may either increase or decrease Zarontin® levels.

Care During Treatment With Zarontin®

You should take the medicine as prescribed by your physician. If you are late in taking a dose by 2-3 hours, you should take it. If you miss a dose altogether, you should wait until the next dose and take the prescribed amount, or consult your physician. Report any unusual rashes, fevers, or other side effects.

Possible Contraindications to the use of Zarontin®

A history of liver or kidney disease or unusual reactions to succinimides.

Not everyone experiences side effects. There may be other side effects not appearing above. For a complete list, consult your doctor, nurse, or pharmacist. More detailed sources of information on side effects include the drug’s prescribing information sheet, the Physician’s Desk Reference, or pharmaceutical company which produces the drug.

Link to product information here.

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