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FDA Pulls Generic Version of Wellbutrin XL 300 mg
By Brendan McLean, NAMI Communications Coordinator
Last week the U.S. Food and Drug Administration issued a press release stating that Budeprion XL 300 mg, a generic version of Wellbutrin (bupropion) XL 300 mg, did not produce the same therapeutic results.
Budeprion XL 300 mg, which is manufactured by Impax Laboratories, Inc., and marketed by Teva Pharmaceuticals USA, Inc. was approved in December 2006. In order for a generic drug to be marketed, it must be determined to be bioequivalent. Bioequivalent products are those that demonstrate a similar rate and extent of absorption of the therapeutic ingredient (the drug). Studies were conducted, however, only on the 150 mg version of the drug and then extrapolated to the 300 mg version.
While this was the FDA’s mode of approval for generic drugs, in the release the FDA stated that the method was “no longer appropriate… and the Agency is revising its guidance to industry for how to conduct premarket bioequivalence studies in generic bupropion products.”
Soon after the drug was approved, individuals who had begun taking the generic form of the drug discovered that the drug was not as effective as the brand name version. The FDA requested Impax/Teva to conduct a study on the efficacy of the 300 mg version of the drug. However, the study was ended in late 2011 before results were established because an adequate amount of patients were unable to be recruited for the study.
Because of public interest, the FDA launched its own study in 2010. In August 2012 the results became available and revealed that “Budeprion XL 300 mg tablets fail to release bupropion into the blood at the same rate and to the same extent as Wellbutrin XL 300 mg.”
Four other manufacturers—Anchen, Actavis, Watson and Mylan—currently make generic forms of Wellbutrin XL 300 mg. The FDA has asked each of them conduct their own bioequivalence studies to assess their effectiveness and will evaluate their validity when the data are received.