Chantix, a smoking cessation drug made by American multinational pharmaceutical corporation Pfizer, is eight times more likely to be linked to cases of suicidal behavior or depression when compared to other smoking cessation drugs, according to a study released on Wednesday.
The study, published by PLoS ONE – a publication of the Public Library of Science, a U.S. non-profit organization – reviewed adverse drug event reports sent to the US Food and Drug Administration (FDA) from 1998 to 2010 by health professionals, consumers, and drug manufacturers whenever a serious adverse event or reaction occurs. The study focused on reported events having serious outcomes including hospitalization, disability, and life-threatening events and compared Chantix (or Varenicline, marketed as Champix outside the U.S.) with Bupropion (also marketed as Wellbutrin, Zyban, Voxra, Buderprion, or Aplenzin).
The study found that, out of about 3,200 reports of self-injury or depression linked to Chantix, about 2,900 cases (90%) were related to Chantix. The drug was approved for use in the U.S. for only four years of the more than 12 years of the data included in the study. 229 cases of suicidal behavior or depression were found to be related to Bupropion and 95 cases related to other nicotine replacement drugs.
Pfizer defended the drug saying, in a statement, the study’s analysis relied on reports of serious events to the FDA from a range of sources which often lack important medical information, making them unsuitable for studies like this.
In the statement, Pfizer also said, “It is important to remember that post-marketing reports do not establish a cause and effect relationship between a medicine and a reported adverse event.”
One of the study’s co-authors said that regulators and patients need to balance the risks of smoking with the benefits of quitting. Smoking is related to one in five deaths in the United States each year.
The co-author also stated only 10% of patients treated with the drug stopped smoking, one year after they started taking the drug, citing this fact as the drug’s slight benefit.
The co-authors said that even though Chantix labelling includes strong warnings about side effects, they want to see the drug used as an alternate treatment when other drugs or treatment methods have failed.