Ethosuximide is Best Treatment for Common Childhood Epilepsy

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For the first time, experts have accumulated definitive evidence that a specific drug, ethosuximide, is the most effective way to treat the common form of childhood epilepsy known as childhood absence epilepsy syndrome. Ethosuximide was first approved for treatment of epilepsy in 1960.

Nearly 3 million people in the United States have some form of epilepsy, according to the Epilepsy Foundation, and there are about 200,000 new cases of seizures disorders and epilepsy diagnosed every year. Approximately 120,000 people who have epilepsy are younger than 18, and 45,000 children younger than 15 develop epilepsy each year. The good news is that there is a trend toward a decreased incidence in children.

When epilepsy is diagnosed, no cause can be determined in 70 percent of new cases. Males are slightly more likely to develop epilepsy than females, and there is a greater incidence among African Americans and socially disadvantaged populations.

Ethosuximide Study
The new study included 32 pediatric epilepsy centers across the United States, which are part of the National Institute of Health’s Childhood Absence Epilepsy Study Group. The study group conducted a comparison of three drugs used to treat childhood absence epilepsy syndrome, in which children experience frequent seizures that do not involve convulsions but which cause them to stare for up to 30 seconds at time. These episodes tend to occur in clusters.

A total of 453 children who had been diagnosed with childhood absence epilepsy between July 2004 and October 2007 were enrolled in the sixteen-week study. Three treatments were evaluated: ethosuximide, valproic acid, and lamotrigine. The investigators increased the drug doses incrementally until each child was no longer experiencing seizures.

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Ethosuximide and valproic acid were significantly more effective than lamotrigine when it came to controlling seizures, and there were no intolerable adverse effects. However, ethosuximide was associated with significantly fewer negative effects on attention than valproic acid.

Currently underway is a long-term follow-up extension of the study that includes children taking the medication and not experiencing seizures, those taking the medication but still having seizures, and those who took medication, stopped having seizures, and then stopped taking the medication. The extended part of the study is slated to run for five years.

Childhood Absence Epilepsy Syndrome
Childhood absence epilepsy syndrome, which is also known as petit mal epilepsy, accounts for 2 to 4 percent of all cases of epilepsy in children. The syndrome is inherited. Although the syndrome is generally benign, about half of the children experience a generalized tonic clonic seizure, in which individuals have stiffening and jerking of the limbs. The risk of such seizures is greater if the child has neurological deficits, and the risk is reduced if the seizures are quickly treated with medication.

Children who have childhood absence epilepsy syndrome are otherwise normal, and often have IQ scores 10 points above average. Forty percent of them outgrow the seizures.

The results of this study identified ethosuximide as the most effective treatment for children who have a common form of epilepsy. Colin Roberts, MD, Oregon Health & Science University Doernbecher Children’s Hospital’s main investigator for the study and director of OHSU Doernbecher’s Pediatric Epilepsy Program, notes that this research has laid the foundation for future studies that will help experts uncover the best ways to properly care and treat childhood epilepsy.

SOURCES:
Epilepsy Foundation
Oregon Health & Science University press release, Mar. 11, 2010

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