After Earlier Exoneration, Paxil Linked to Adult Suicide AttemptsAug 22, 2005 | www.medpagetoday.com Fifteen years after dismissing any association between the antidepressant Paxil (paroxetine) and adult suicide attempts, Norwegian researchers say a re-analysis of the data has found an association after all.
In a review of 16 studies that compared Paxil with placebo, the researchers found seven suicide attempts among those taking the drug, versus only one among those on placebo, said Ivar Aursnes, M.D., Ph.D., and colleagues at the University of Oslo.
"Patients and doctors should be warned that the increased suicidal activity observed in children and adolescents taking certain anti-depressant drugs may also be present in adults," Dr. Aursnes said.
However, the drug's maker, GlaxoSmithKline, responded that the study was flawed and would only cause "confusion and unnecessary concern" among patients.
The Norwegian study, published in the online journal BMC Medicine, appeared in the light of warnings in April by European health regulators that several anti-depressants, including Paxil, shouldn't be used to treat children because of a risk of suicide.
It also comes after two meta-analyses in February in the British Medical Journal. One of these found an association between adults taking selective serotonin re-uptake inhibitors (SSRIs) and suicidal activities. The other found "weak evidence of an increased risk of self harm."
The February earlier meta-analyses were incomplete, Dr. Aursnes said, because one of them did not distinguish between suicidal attempts and suicidal ideation, and the other reported on published data only.
For this new study, the Norwegian researchers reviewed the clinical data on Paxil, as they were presented to regulatory agencies in 1989. Much of the data were unpublished and included primary data and individual case descriptions, Dr. Aursnes said.
All of the studies were double-blind randomized trials; there were 916 Paxil-treated and 550 placebo-treated patients. No suicides were recorded.
Using Bayesian statistical methods, the authors assigned different prior probabilities (based on the results of studies from children) of increased suicide attempts in the Paxil group and then calculated a posterior probability using the data from the unpublished studies in adults. Using prior probabilities of 0.42, 0.58, and 0.75, the posterior probabilities of increased suicide attempts with Paxil were 0.79, 0.85, and 0.90 respectively.
"Although we report a small data set," Dr. Aursnes and colleagues said, "the data strongly suggest that the use of SSRIs is connected with an increased intensity of suicide attempts per year."
The finding also suggests, the researchers said, "that the recommendation of restrictions on the use of paroxetine for children and adolescents recently conveyed by regulatory agencies should be extended to include usage by adults."
In a statement today, GlaxoSmithKline questioned the finding and said it "serves only to cause confusion and unnecessary concern for patients."
The company said the Norwegian analysis "is misleading as it focuses on incorrectly selected data, collected 15 years ago, which formed part of the successful regulatory submission in 1989 for use of paroxetine to treat depression in adults."
Also, the company said, the study "fails to acknowledge the current body of data, which is significantly more extensive," noting that European regulators in 2005 "reaffirmed the positive benefit-risk for paroxetine's use in the treatment of depression and anxiety disorders in adults."