Examples

These medicines usually require several doses each day. A newly approved, once-daily dose of divalproex sodium is also available (Depakote ER).

Divalproex sodium and valproic acid are available as capsules and tablets, and valproic acid also has a syrup form. Divalproex sodium also comes in a sprinkle form that is a good choice for children. Valproate sodium is available as a shot (injection).

Divalproex sodium irritates the stomach less than valproic acid.

How It Works

It is not clear how these different types of valproic acid prevent seizures, but they may prevent seizure activity by increasing levels of a certain chemical in the brain.

Why It Is Used

Valproic acid is a drug of choice for:

• Generalized epilepsy of unknown cause that produces more than one type of seizure.
• Absence seizures. If a person has absence seizures as well as other types of seizures, valproic acid usually works well because it can control several types of seizures.
• Myoclonic seizures, such as those caused by juvenile myoclonic epilepsy.
• Valproic acid is also considered a first-line drug for treating partial seizures.

How Well It Works

Valproic acid prevents seizures in most people who use it to control complex partial seizures and absence seizures. It is also effective against generalized tonic-clonic seizures, myoclonic seizures, and atonic seizures.¹

Side Effects

Common side effects of valproic acid include:

• Nausea, vomiting, and stomach cramps. Divalproex sodium irritates the stomach less than valproic acid.
• Weight gain.
• Tremors and shaking.
• Temporary hair loss.
• Irregular menstrual cycle.

These side effects may increase as the dosage needed to control seizures increases. Because valproic acid levels in the body tend to go up and down, some side effects may vary from day to day or even within a single day. Nausea and stomach problems usually go away after the body adjusts to the drug. Hair loss, weight gain, and tremors often come with long-term use of the drug.

Skin rash, a very common side effect of antiepileptic drugs, is less common with valproic acid. Valproic acid tends to have less effect on your thinking, memory, or learning processes than other antiepileptic drugs (as long as the drug levels in your bloodstream do not become too high).

The U.S. Food and Drug Administration (FDA) has issued a warning on antiepileptic medicines and the risk of suicide and suicidal thoughts. The FDA does not recommend that people stop using these medicines. Instead, people who take antiepileptic medicine should be watched closely for warning signs of suicide. People who take antiepileptic medicine and who are worried about this side effect should talk to a doctor.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

It may take time and careful, controlled adjustments by you and your doctor to find the combination, schedule, and dosing of medicines to best manage your epilepsy. The goal is to prevent seizures while causing as few unwanted side effects as possible. After the most effective medicines program is determined, it is important that you follow it exactly as prescribed.

• Adverse effects. The weight gain that can result from use of valproic acid can be quite significant and is a major concern for some people. High levels of valproic acid may also cause severe tremors that make certain types of work and activities quite difficult.
• Serious health risks. Valproic acid may cause liver damage (called hepatotoxicity). This liver damage can be fatal, although only children younger than age 10 have died from it. Children age 2 and younger who are taking more than one drug and have other brain and nervous system disorders are at highest risk. Routine blood tests and careful monitoring can lower the risk. The risk of liver disorders caused by valproic acid is extremely low in adults.
• Drug interactions. Many medicines for epilepsy can interact with other medicines you may be taking. This means that your epilepsy medicine may not work as well, or it may affect the way another medicine you are taking works. Some of these interactions can be dangerous. It is important to tell your doctor about all the medicines, herbal pills, and dietary supplements you are taking. Valproic acid is a good choice for women taking birth control pills, because it will not reduce the effectiveness of the pills.
• Risk of birth defects. All medicines for epilepsy have some risk of birth defects. But the risk of birth defects needs to be carefully compared to other risks to the baby if the mother stops taking her epilepsy medicine. If you are thinking about becoming pregnant, it is important to plan ahead and talk with your doctor about the benefits and risks of taking epilepsy medicine during your pregnancy. It you are already pregnant, it is not too late. The best thing to do is talk to your doctor about your pregnancy before you make any changes to the medicines you are taking.
• Cost. Valproic acid is expensive. If cost is a problem, your doctor can help you figure out whether a less expensive drug will work just as well as valproic acid.
• Other concerns. For some people, valproic acid may cause side effects or carry risks that are not yet fully known. Report any unexpected side effects or problems to your doctor.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

Citations

1. Drugs for epilepsy (2005). Treatment Guidelines From the Medical Letter, 3(39): 75–82.