May 16, 2003 -- Memory and other cognitive problems are more common among epilepsy patients taking the popular anti-seizure drug Topamax than in those taking an older mediation, new research suggests.
The findings may have broad implications because Topamax also shows promise in the treatment of obesity, migraines, and even alcoholism. In a study released Friday, researchers in Texas reported that alcoholics taking the drug had dramatic reductions in episodes of binge drinking. Another study, reported in February, found the drug to be highly effective in reducing binge eating.
Topamax was introduced in 1996 in a wave of new anti-seizure drugs. Its use was quickly associated with numerous cognitive side effects, but it has not been clear if these side effects occur more frequently than with other anti-seizure drugs.
Georgetown University Hospital researchers compared memory and other cognitive side effects among patients treated with Topamax and those taking the older anti-seizure drug Depacon. Both drugs were given in combination with the standard anti-seizure drug Tegretol. The study was funded by Topamax manufacturer Ortho-McNeil Pharmaceuticals and was published in the May issue of the journal Neurology.
The researchers found cognitive side effects among patients taking Topamax to be "slightly worse overall" than in patients taking the older drug. Specifically, patients on the newer medication had more verbal memory problems, including word finding difficulty and word fluency issues.
Lead investigator Kim J. Meador, MD, tells WebMD that the cognitive problems are most pronounced in patients who are started on high doses of the drug or have their dosages increased too quickly. He says problems can be minimized in most patients by gradually increasing dosages.
"Some patients have no problems at all with the drug, and others will have problems no matter how careful you are," he says. "Even if we do everything right, there is still a subset of patients that will experience cognitive problems."
Epilepsy specialist Marc Dichter, MD, PhD, says the choice of an anti-seizure drug is complicated because most of the available drugs seem to work equally well but have differing side effect profiles. He says a growing number of his patients are asking for Topamax because they have heard it can help them lose weight. Dichter is director of the University of Pennsylvania Health Center epilepsy program.
For many patients, cost is also an issue. Topamax and the other new epilepsy drugs cost from $150 to $200 a month, compared with just $20 or $30 a month for older drugs such as Dilantin. Dichter says he believes Topamax will stay popular among patients who do not experience cognitive problems because it promotes weight loss.
"Many of these drugs cause weight gain, and Dilantin causes hair growth," he says. "If I ask a young female patient if she would rather be on a drug that is going to make her grow facial hair or one that is going to help her lose weight, her answer isn't going to be a big surprise."