Predicting Success Rates for Epilepsy Drugs
50% of Patients Seizure-Free After Trying First Anti-Seizure Drug
By By Salynn Boyles
WebMD Health News
Reviewed By Laura J. Martin, MD
May 9, 2012 -- Half of all epilepsy patients who are initially started on one anti-seizure drug remain seizure-free for at least a year, a new study confirms.
Among patients followed for as long as 26 years, initial response to drug treatments strongly predicted future seizure control.
Yet less than 1% of patients who failed to respond to three anti-seizure drug regimens achieved adequate seizure control on subsequent drug treatments even though some were treated with as many as nine different drugs or drug combinations.
The findings make it clear that epilepsy patients who are candidates for surgery or other non-drug treatments should be considered for these procedures earlier rather than later, says neurologist Patricia E. Penovich, MD, of the University of Minnesota and the Minnesota Epilepsy Group in St. Paul.
"These patients don't have to wait until they have failed five or six different drug regimens," she tells WebMD. "If their seizures are not controlled by the first few medications it is reasonable to consider surgery."
More Than a Dozen Anti-Seizure Drugs
Roughly 2.7 million Americans have epilepsy, and about 1 in 10 people will experience a seizure at some point in their lifetime, according to the Epilepsy Foundation.
More than a dozen different drugs can be used to control seizures, and decisions about which medication to try first are made by considering individual patient characteristics, including age, sex, seizure type, and financial circumstance.
The new research is among the first to examine long-term outcomes in newly diagnosed patients, says researcher Patrick Kwan, MD, PhD, of Australia's University of Melbourne.
The study included about 1,100 epilepsy patients in Scotland and followed them from their first drug treatment for as few as two years and as many as 26 years.
Patients were considered seizure-free if they had no seizures for at least a year without changing their drug regimen.
If seizures continued, a second drug was given, either alone or in combination with the first. And if seizures still were not controlled, different drugs or drug combinations were tried, with some receiving up to nine different drug regimens.
1 in 4 Patients Never Seizure-Free
Among the major findings:
- 50% of patients were seizure free on the first drug they tried and an additional 13% were seizure free after trying a second drug.
- 37% of patients became seizure-free within six months of starting treatment, and an additional 22% became seizure-free after more than six months.
- 1 in 4 patients were never free of seizures for a complete year during the study period.
The study appears online ahead of publication in the May 15 issue of the journal Neurology.
In an accompanying editorial, Penovich and neurologist Michael Gruenthal, MD, PhD, of the Albany Medical Center in New York, write that the new research identifies important patterns of treatment response.
They conclude that failure of two drug regimens in patients who take their medications as directed strongly predicts poor response to future drug therapies.
"We interpret this as compelling evidence that patients who do not respond to two regimens should be offered additional evaluations to verify the diagnosis of epilepsy and identify potential opportunities for surgical treatment," they write.
Brodie, M.J., Neurology, May 15, 2012.
Patricia E. Penovich, MD, clinical professor, department of neurology, University of Minnesota School of Medicine; neurologist, Minnesota Epilepsy Group PA, St. Paul, Minn.
News release, American Academy of Neurology.
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