ADELAIDE, Australia, Sept. 17 (UPI) -- A new analysis of clinical trials for the use of paroxetine, sold as Paxil, to treat depression in teenagers has called into question its effectiveness, as well as the alleged mislabeling of significant side effects.
The drug has been widely prescribed for teenagers since its approval for that use by the Food and Drug Administration in the early 2000s. The original study, referred to as Study 329, was questioned upon its publication in 2001 at least partially because of ties between the lead researcher and the pharmaceutical manufacturer.
The new analysis of study data, published in the British Medical Journal, found the drug had no clinical or significantly different effect on depression from placebo treatment. There were, however, side effects seen in patients who were given the actual drug, including attempted suicides, attempts at self-harm, and behaviorally adverse events.
"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," said Jon Jureidini, a researcher at the University of Adelaide, in a press release. "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. Our study also revealed that paroxetine was no more effective at relieving the symptoms of depression than a placebo."
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Study 329 was conducted at 12 psychiatric facilities between 1994 and 1998 with 275 adolescents who had been diagnosed with major depression for at least eight weeks. The participants were randomized in the trial to receive eight weeks of treatment with paroxetine, imipramine, or a placebo.
The original study found that, based on the Hamilton depression scale, or HAM-D, scores, paroxetine lowered participant scores by 10.7, imipramine lowered it by 9.0, and placebo lowered it by 9.1. In re-evaluating this data, the researchers called this change "not statistically or clinically significantly different."
The researchers add that the group that received paroxetine, or Paxil, had clinically significant increases in suicidal ideation and behavior, as well as other serious adverse events. Participants who took imipramine, sold as Tofranil, also showed an increase in cardiovascular problems, which were blamed on the drug.
The conclusions of researchers in the new analysis is based not only on the information published in the original study, but using individual patient data not originally considered or published.
"Our reanalysis of Study 329 came to very different conclusions to those in the original paper," Jureidini said. "We also learned a lot about incorrect reporting and the considerable fall out that can be associated with distorted data. Regulatory research authorities should mandate that all data and protocols are accessible. Although concerns about patient confidentiality and 'commercial in confidence' issues are important, the reanalysis of Study 329 illustrates the necessity of making primary trial data available to increase the rigor of evidence-based research."
This new look at the original study by SmithKline Beecham, now called GlaxoSmithKiline, on using paroxetine and imipramine with adolescents, controversial since it's original publication, is part of a larger movement by researchers to more closely examine their colleagues' work, researchers wrote in an editorial published by the British Medical Journal with the reanalysis.
"This paper is alarming, but its existence is a good thing," Brian Nosek, a professor of psychology at the University of Virginia, told the New York Times. "It signals that the community is waking up, checking its work and doing what science is supposed to do -- self-correct."
