What About Topamax?

What is Topamax?

Topamax (topiramate), developed by Johnson & Johnson, is a drug widely used to treat epilepsy and seizures.

During clinical trials, researchers discovered the that users of Topamax lost up to 12 percent of their body weight after taking the drug for two years.

Johnson & Johnson subsequently began clinical trials of Topamax for weight loss, and from a weight-loss standpoint, the results were very encouraging.

The study consisted of approximately 701 obese individuals who had qualified for the trial by losing 8 percent of their body weight over a two-month period by restricting caloric intake.

Some of the participants were put on a high dose of Topamax, some on a low dose, and some on a placebo.

Ten months into the study, dieters who took Topamax had lost almost twice as much weight as those taking placebo pills. Dieters taking high-dose Topamax had lost 17 percent of their initial body weight, those taking low-dose Topamax had lost 15 percent of their initial body weight, and dieters taking the placebo had lost 9 percent of body weight.

At that point, Johnson & Johnson discontinued the trial because of negative side effects. "Most adverse events were linked to the central nervous system," the researchers reported in the October 2004 issue of the journal Obesity Research..

The most common side effect for those taking Topamax was paresthesia, a tingling, "pins and needles" sensation in the extremities, which occurred in 73 percent of patients taking the higher dose and 46 percent of patients taking the lower dose of the drug.

Topamax use was also linked to problems with memory. Some 18 percent of dieters in the trial taking higher doses of the drug reported memory problems, compared with 14 percent of those taking the lower dose and 6 percent of those taking a placebo.

Johnson and Johnson subsequently said it was attempting to develope a time-release version of the Topamax that it hoped would minimize side effects and be more appropriate for dieters.

But in December 2004, J&J said that it was discontinuing clinical development of Topamax for obesity because "the controlled release formulation did not provide significant advantages in this population compared to previously conducted studies using the immediate release formulation."