Valproic acid for epilepsy

Examples

Generic Name	Brand Name
divalproex sodium	Epival ECT, Epival ER
valproate sodium	Epiject IV, Deproic Syrup
valproic acid	Depakene

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

Divalproex sodium and valproic acid are available as capsules and tablets, and valproic acid also comes in 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) or in syrup form.

Divalproex sodium irritates the stomach less than valproic acid.

How It Works

It is not clear how valproic acid prevents seizures, but it 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. Ethosuximide is the other drug of choice. If a person has absence seizures as well as other types of seizures, however, valproic acid usually works better because it can control several types of seizures.
• Myoclonic seizures, such as those caused by juvenile myoclonic epilepsy. Clonazepam may be used when valproic acid does not work.

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 generalized epilepsy and absence seizures. It is as effective against generalized tonic-clonic seizures as phenytoin and as effective against absence seizures as ethosuximide.

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).

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 medication to best manage your epilepsy. The goal is to prevent seizures while causing as few unwanted side effects as possible. Monitoring medication levels in your bloodstream can help keep your dose in the appropriate range. Once the most effective medication 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.
• Risk of birth defects. Valproic acid has been linked to an increased risk of spina bifida and other birth defects, such as cleft palate and heart, limb, and genital problems.¹ Women of child-bearing age who are not using contraception should not take valproic acid.
• Cost. Valproic acid is expensive. However, the cost of this medication is usually covered by your provincial health plan.
• Other concerns. Valproic acid is a good choice for women taking birth control pills because it will not reduce the effectiveness of the pills.

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

Author:	Douglas Dana Merrill Hayden	Last Updated: February 2, 2006
Medical Review:	Adam Husney, MD - Family Medicine Tom Bailey, MD - Family Medicine Steven C. Schachter, MD - Neurology
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