FDA clears generic Wellbutrin.

The generic formulation of Wellbutrin XL (300 mg) is bioequivalent to the brand, the Food and Drug Administration has determined. The agency began a review of generic bupropion after receiving 85 adverse event reports in the first 6 months of 2007. Seventy-eight patients said they had experienced loss of antidepressant effect when they were switched from the branded product to the generic manufactured by Teva Pharmaceutical Industries Ltd. The Teva product was approved in 2006, but at the 150-mg dose and based on bioequivalence to 150 mg of Wellbutrin XL, according to the FDA, which noted that the pharmacokinetic profile was not expected to differ between the 150-mg and 300-mg doses. After the rash of adverse event reports, the agency again reviewed the bioequivalence data and the literature on natural history of depression. The FDA concluded that there was no difference between the two products. Also, if there was a link to the generic, there should have been many more reports, said the FDA, noting that by early 2007, at least 40% of bupropion prescriptions were for the generic. The agency added, "The recurrent nature of major depressive disorder offers a scientifically reasonable explanation for the reports of lack of efficacy following a switch to a generic product."