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Common uses
Valproic acid is a medication used for controlling seizures in people with epilepsy. In particular, valproic acid is approved to control the following types of seizures:
* Complex partial seizures
* Simple or complex absence seizures.
Epilepsy is a brain condition that occurs when there are sudden, brief changes in how the brain's electrical system works. This change in brain activity can lead to a seizure (see Epilepsy Symptoms). Depending on which part of the brain is affected, a seizure may affect the person's consciousness, body movements, emotions, or senses (taste, touch, smell, vision, or hearing).
In over half of all cases, the cause of epilepsy is not known. Epilepsy treatments may include:
* Medications (see Epilepsy Medication)
* Surgery (see Epilepsy Surgery)
* Dietary changes (see Epilepsy Diet)
* Biofeedback.
Valproic acid works by increasing the amount of gamma-aminobutyric acid (GABA) in the brain. GABA is a natural brain chemical that stops or slows down other brain signals. Increasing GABA helps prevent the abnormal brain signals that lead to a seizure. It is thought that valproic acid may also prevent seizures by affecting sodium channels in the brain.
Before using
* There have been cases of liver failure caused by valproic acid. Children under two years old are at especially high risk, especially children with mental retardation, brain damage or disease, or certain other health problems. Valproic acid is not approved for children less than 10 years old and should rarely be used in young children, due to the risk of liver damage.
* You should not take valproic acid if you have liver disease. Also, you should not take it if you have a urea cycle disorder (a problem with the enzymes that clear ammonia from the body, leading to high ammonia levels in the blood), as valproic acid may make this condition worse. You should be evaluated for a urea cycle disorder if you have a history of:
o A brain disease or problem associated with pregnancy
o Unexplained brain disease or problems
o Unexplained mental retardation
o High ammonia levels in your blood
o Vomiting and lethargy that comes and goes regularly.
* Valproic acid can cause pancreatitis (inflammation of the pancreas), which may be quite dangerous. Let your healthcare provider know immediately if you have any signs of pancreatitis, including:
o Severe abdominal pain (stomach pain)
o Nausea and vomiting
o Loss of appetite.
Possible side effects
Most of what is know about valproic acid side effects is based on clinical trials of Depakote, a similar medication. Depakote is changed in the body into the same medication as valproic acid. However, it is important to understand that valproic acid may be more likely to cause certain side effects when compared to Depakote.
In these studies, some of the most common side effects of Depakote (which is similar to valproic acid) included:
* Shakiness (tremors)
* Nausea
* Headaches
* Drowsiness
* Vomiting
* Weakness
* Dizziness
Additional information
The recommended starting dose of valproic acid for complex partial seizures is based on your weight -- 10 mg to 15 mg per kg total per day (about 4.5 to 6.8 mg per pound per day).
If the total daily dose is more than 250 mg, it should be split up into two or three smaller doses. Your healthcare provider will probably increase your dose slowly until your seizures are controlled or until you experience bothersome side effects.
Drug interactions
Valproic acid can potentially interact with many other medications. Some of the medicines that may lead to valproic acid drug interactions include:
* Amitriptyline (Elavil)
* Aspirin
* Carbamazepine (Epitol, Equetro, Tegretol, Tegretol XR)
* Chlorpromazine (Thorazine)
* Clonazepam (Klonopin)
* Diazepam (Valium)
* Ethosuximide (Zarontin)
* Felbamate (Felbatol)
* Lamotrigine (Lamictal)
* Meropenem (Merrem)
* Nortriptyline (Pamelor)
* Phenobarbital (Luminal)
* Phenytoin (Dilantin, Phenytek)
* Primidone (Mysoline)
* Rifampin (Rifadin)
* Tolbutamide (Orinase)
* Topiramate (Topamax)
* Warfarin (Coumadin, Jantoven)
* Zidovudine (Retrovir).
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