Zarontin (Ethosuximide) for Treating Seizures

This medication is mainly for absence seizures

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Zarontin (ethosuximide) is a prescription anti-epileptic medication primarily used to treat a specific type of seizure known as an absence seizure. The drug is suspected to work by combatting changes in the electrical activity in the brain that give way to these seizures, which reduce consciousness for a brief period of time. Ethosuximide is generally considered a safe and effective medicine. But like all anti-epileptic medications, it carries a risk of increasing suicidal thoughts in certain people.

Absence seizures are more common in children than adults. It is important to get treatment early on, and ethosuximide is considered the best option to try first. These seizures can reduce a child's academic performance and pose safety challenges, and children with absence seizures will need to avoid certain activities until their condition is under control.

Indication

Zarontin is approved by the U.S. Food and Drug Administration (FDA) for people with absence seizures, and it has been used for this for many years. It is one of the most common drugs prescribed for this condition. (Lamotrigine and valproate are two other anti-epileptic drugs commonly given for this type of seizure.)

In fact, in a 2017 review of studies on ethosuximide, researchers concluded that this medication is the best first-line single treatment (monotherapy) for children and adolescents with absence seizures. They add, though, that in someone who also has generalized tonic-clonic seizures, valproate is a more appropriate treatment.

Less commonly, Zarontin is given to people with other seizure types, usually in addition to other drugs.

How It Works

Ethosuximide’s active ingredient is a chemical called alpha-ethyl-alpha-methylsuccinimide. It is not exactly clear how this drug works. Like other ​anti-epileptic drugs, though, it helps suppress abnormal electrical activity in the brain.

Specifically, ethosuximide may work by changing how often a specific type of calcium channel in the brain opens and closes. This affects the brains excitability (how often certain neurons send signals), which helps stabilize the brain’s electrical activity and, thus, help prevent absence seizures in particular.

Administration

Zarontin is available in both capsule and liquid preparations. It's generally started at a low dose that's increased gradually under the supervision of a doctor. The goal is to reach a dose that will control seizures with minimal side effects. The final dosing will vary based on a patient’s weight and other factors.

Ethosuximide should be stored at room temperature away from light. It can be taken with or without food.

Some people need to take Zarontin in combination with other anticonvulsant drugs (such as valproate) to control their seizures. Make sure to tell your doctor about all the medicines that you take, including over-the-counter medicines, since these can affect how well ethosuximide works.

To minimize your risk of seizures, take ethosuximide exactly as prescribed. If you accidentally miss a dose, go ahead and take it as soon as you remember. However, if it is already time for another dose, don’t double up. Just take your regular amount.

Overdose Warning

If you accidentally take more Zarontin than you should, contact your doctor immediately, or go to your emergency care center. A major overdose of ethosuximide might cause serious problems like reduced breathing. If this occurs, health professionals will need to intervene to decrease the amount of drug in your body.

Stopping Zarontin

Taking ethosuximide suddenly can cause seizures. If you're having a problem with this drug, contact your doctor. Lowering your dosage may help with side effects, and your physician can give you instructions on how to slowly reduce your dosage until it's safe to stop taking the medication.

Side Effects

Like all medications, ethosuximide comes with potential side effects. The most common ones include:

  • Abdominal discomfort
  • Nausea
  • Drowsiness
  • Headache
  • Dizziness
  • Rash
  • Problems with the liver or kidneys (rare)

Because of the drowsiness that ethosuximide can cause, it is important to be cautious about driving and other potentially dangerous tasks. This is especially important if one is just getting used to the medication.

In children, studies show ethosuximide can cause attentional dysfunction, psychomotor slowness, and a drop in alertness. Researchers stated that these effects were mild and comparable to those of other anti-epileptic drugs.

Rarely, Zarontin can also cause a serious problem in which a person’s blood cells aren’t working well. This might show up as signs of an infection (like sore throat and fever) or as symptoms of easy bruising or very pale appearance. If these occur soon after taking ethosuximide, contact your doctor.

Due to the potential for problems with blood cells, the liver, and the kidneys, you may need periodic blood and urine tests while taking this medication.

Suicidal Thoughts

It’s important to be aware of one uncommon but very significant potential side effect of ethosuximide (and all anti-epileptic drugs, for that matter): suicidal thoughts.

Watch out for any worsening signs or symptoms of depression or other unusual changes in a person's mental state or behavior. If it's you taking the drug, try your best to acknowledge any of your own. If these emerge, seek professional help right away. Of course, not all people taking ethosuximide will experience this side effect.

While this is obviously a concern, untreated seizures also carry their own risks and can increase the risk of depression themselves. A healthcare provider can help weigh the risks and benefits of medication for a particular individual.

Contraindications

People who are known to be allergic to other medicines in the succinimide family should not take Zarontin.

Ethosuximide may increase the risk of birth defects, so you should notify your doctor if you find out you're pregnant. Await instruction instead of immediately stopping the drug.

Zarontin is not recommended while breastfeeding due to concerns about abnormalities in weight and developmental milestones.

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