A cheaper, generic version of GlaxoSmithKline Plc’s Wellbutrin XL antidepressant is just as safe and effective, despite complaints from some patients, the U.S. Food and Drug Administration said on Wednesday.

The FDA said it received 85 reports from patients who switched from Wellbutrin XL to a cheaper generic made by Teva Pharmaceutical Industries Ltd, including 78 who said they slipped back into depression.

Other patients reported new or worsening side effects, including headaches, fatigue, anxiety and digestion issues.

“The question is whether the reported lack of efficacy and/or new onset side effects in these patients who switched suggest a problem with the generic product ... or have some other explanation,” the FDA said in a statement on its website.

Agency scientists reviewed the two drugs, which both use formulations of a chemical called bupropion, and found the data did not show that the problems stemmed from any differences between the two drugs.

One factor that could account for the reported problems is the natural recurrence of depression, which can happen despite treatment, the FDA said.

Half of the patients who went back on the name-brand drug improved, the agency said, adding that it would continue to monitor the issue.

By Susan Heavey
WASHINGTON (Reuters)