A new study from the University of Adelaide found that the original trial on paroxetine reported that it was effective when it may not have been. The second look also found that the medication had serious side effects.
"Although concerns had already been raised about Study 329, and the way it was reported, the data was not previously made available so researchers and clinicians weren't able to identify all of the errors in the published report," said lead author of the new study Jon Jureidini, MD, in a press release.
Dr. Jureidini, a child psychiatrist at Women's and Children's Hospital in Adelaide, and colleagues re-examined Study 329, a randomized, controlled trial conducted in 2001.
The original study included 275 adolescents who had major depression for at least eight weeks. The study patients were assigned to one of three groups.
The first group was treated with 20 to 40 milligrams of paroxetine. The second group received imipramine (brand name Tofranil), an antidepressant medication. The third group took placebos, or fake pills.
The purpose of the study was to determine whether paroxetine was effective and whether the drug has serious side effects. The original study was funded by SmithKline Beecham (now GlaxoSmithKline), which makes paroxetine.
Doctors and scientists raised concerns about Study 329 when it was originally published. The current study was the first independent analysis of the original data.
Dr. Jureidini and colleagues found that neither paroxetine nor imipramine were effective when compared to placebo.
They also found that the use of paroxetine increased the risk of suicide. Imipramine appeared to increase the risk of heart problems.
"It wasn't until the data was made available for re-examination that it became apparent that paroxetine was linked to serious adverse reactions, with 11 of the patients taking paroxetine engaging in suicidal or self-harming behaviors compared to only one person in the group of patients who took the placebo," Dr. Jureidini said. "Our study also revealed that paroxetine was no more effective at relieving the symptoms of depression than a placebo."
Dr. Jureidini added, "This is highly concerning because prescribing this drug may have put young patients at unnecessary risk from a treatment that was supposed to help them.”
This new analysis of Study 329 was published in the September issue of The BMJ.
The new study did not receive outside funding. Co-author Dr. David Healy acted as an expert witness for plaintiffs in legal cases involving paroxetine. Dr. Jureidini also acted as an expert witness against GlaxoSmithKline in a class action suit over Study 329.