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Zarontin is an oral capsule consisting of an anticonvulsant (anti-epileptic) drug called ethosuximide. We carry the brand medication Zarontin in 250mg. 

Zarontin is used either alone or with other medications to treat “petit mal” seizures, also known as absence seizures, in both children and adults. These types of seizures typically don’t pose any long-term complications and are most common in children. A person having an absence seizure will often have a blank face, staring into space for a few seconds and are often set off by a period of hyperventilation. Like other types of seizures, absence seizures are caused by abnormal activity located in the brain. Most doctors are still unsure why this abnormality occurs.

Zarontin (ethosuximide) is effective at treating absence seizures because it is able to control the abnormal electrical activity located in the brain causing the seizures to occur.

Only take this medication the way that your doctor has directed you too. Taking the incorrect dose can lead to unwanted side effects, ineffectiveness, or adverse interactions; avoid taking more or less of a dose than recommended or stopping the medication before the full prescribed amount is used. You may need frequent blood tests throughout the duration of treatment. Wear a medical ID tag at all times in case of emergency; medical care providers should know you take seizure medications.

Take this medication by mouth once or twice a day, with or without food.


Do not use Zarontin (ethosuximide)

Do not use this product if you are allergic to ethosuximide or to other seizure medications. Do not give this medication to a child under 3 years old.

Dose adjustment or special precautions may be required

To ensure this medication is safe for you, tell your doctor if you have lupus, liver disease, kidney disease, or a history of depression, mood problems, or suicidal thoughts or actions.


Some people, when talking anticonvulsants, have thoughts about suicide; your doctor will likely want to have regular visits to check your progress. Household members and close friends and family should be aware and alert to changes in your mood or symptoms.

This medication can cause harm to a baby if taken by the mother however having a seizure during pregnancy can harm both the baby and the mother. The benefit of preventing seizures from occurring may outweigh the risk towards the baby.

Do not start or stop this medication without first consulting your doctor-even if you find out you are pregnant during treatment.

Tell your doctor if you are breastfeeding; this medication can pass into breast milk and may harm a nursing infant.

Side Effects

Common side effects of Zarontin (ethosuximide) may include:

upset stomach, nausea, stomach pain, loss of appetite; diarrhea, weight loss; hiccups; swelling in your tongue or gums; headache, dizziness, trouble concentrating; or feeling tired.

The above side effects should not alarm you.

Serious side effects of Zarontin (ethosuximide) may include:

fever, chills, flu symptoms, sore throat, feeling very weak; confusion, hallucinations, unusual thoughts or behavior, extreme fear; or worsening seizures.

If you have any of the above side effects, contact your doctor right away.

Please note this is not a complete list of side effects. Not everyone experiences side effects; they are not guaranteed. If you do have side effects and they become unmanageable, consult your doctor about alternate medications.


What should I avoid while being treated with Zarontin?

While being treated with Zarontin, you should avoid being near people who are sick or infected as well as driving after taking the medication as you may become impaired. Tell your doctor if you notice signs of infections and avoid doing hazardous activities until you are fully aware how this medication affects you.

What happens if I drink alcohol while using this medication?

Drinking alcohol with this medication can cause an increase in side effects.

Are there any signs I should watch for and let me doctor know about if I notice them?

You should watch for signs of infection (swollen glands, flu symptoms, easy bruising or bleeding, severe tingling or numbness, muscle weakness, upper stomach pain, jaundice (yellowing of the skin or eyes), chest pain, new or worsening cough, trouble breathing), lupus-like symptoms (joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color), and severe skin reactions (fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling).

What else should I know about Zarontin?

Your kidney function may need to be check regularly while taking this medication. Ensure you keep up with all scheduled doctor appointments.

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