Pfizer and GSK in antidepressant safety probes
pharmafile | September 22, 2015 | News story | Manufacturing and Production | GSK, Paxil, Pfizer, Zoloft, antidepressants, drug safety, paroxetine, sertraline
Two top-selling antidepressants have had their safety records challenges, after the FDA asked Pfizer to change the labelling of its antidepressant Zoloft, and researchers questioned the safety of GSK’s Paxil in children.
The FDA warning is to reflect warnings from researchers who found the medication increases the risk of congenital heart defects in babies whose mothers took it.
Previous claims that Pfizer’s antidepressant Zoloft (sertraline) causes heart defects in babies have resulted in legal claims from patients, who argued the company is not adequately warning pregnant women taking the medication about the possible risks.
The FDA is now taking action, by making the company reflect that some studies link Zoloft to heart defects in babies in the medication’s safety warnings.
Although the majority of Zoloft studies showed that there is no difference in major birth defect risk for women taking Zoloft, the drug’s current label says there are “no adequate and well-controlled studies of pregnant women.”
Earlier this year, two different juries in the US dismissed claims that the drug caused heart abnormalities in babies of women who took the drug while pregnant. However, Pfizer still faces hundreds of similar lawsuits.
Meanwhile GSK’s Paxil (paroxetine) is also under the spotlight after a re-analysis of a study of the use of Paxil in children and adolescents found the drug, used for the treatment of depression and anxiety, was neither safe nor effective in teenagers.
The researchers’ analysis, published in the BMJ, suggested that Paxil is not more effective than placebo in adolescents with major depression.
They also found higher levels of serious side effects which included suicidal thoughts, with apparent discrepancies in the recording of adverse events, prompting them to conclude that “paroxetine was ineffective and unsafe in this study.”
Of 275 trial participants aged between 12–18 years, the analysis found that 11 adolescents who were taking the drug and one in the placebo group developed suicidal or self-harming behaviour. In the original paper, this had been reported as five participants on the drug and one participant on placebo.
Study author Professor David Healy, professor of psychiatry at Bangor University in Wales, says the original study was representative of “the industry approach towards trials in general.”
A GSK spokesperson says: “The findings from this team’s analysis appear to be in line with the longstanding view that there is an increased risk of suicidality in paediatric and adolescent patients given antidepressants like paroxetine. This is widely known and clear warnings have been in place on the product label for more than a decade. As such we don’t believe this reanalysis affects patient safety.”
Yasmita Kumar
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