Serious cardiovascular events associated with Pfizer smoke-cessation drug Chantix

The finding from a new study published in the Canadian Medical Association Journal showed that the use of global drugs behemoth Pfizer’s (NYSE: PFE) anti-smoking pill Chantix/Champix (varenicline) is linked to a 72% increase in risk of hospitalization due to cardiovascular events. The pooled analysis of clinical data in >7,000 smokers indicated that 52 (1.06%) of participants taking Chantix had serious cardiovascular events compared to 27 (0.82%) taking placebo.

Chantix, which first went on sale in the USA in the summer of 2006, has had its safety questioned before and, in July2009, the US Food and Drug Administration told the company to include a boxed warning about the risk of "serious mental health events” and last month also issued a safety notice on cardiovascular risks. Sales of Chantix, also sold as Champix, have been falling since safety concerns emerged, reaching just $755 million last year, down 14% on 2009, although the last quarter saw a year-on-year rise of 32% to $233 million, Pfizer reported with its financial results.

Researchers at a string of university medical in the USA, UK and Germany, led by Johns Hopkins University, evaluated MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, web sites of regulatory authorities and registries of clinical trials, with no date or language restrictions, through September 2010 (updated March 2011) for published and unpublished studies. They selected double-blind randomized controlled trials of at least one week's duration involving smokers or people who used smokeless tobacco that reported on cardiovascular events (ischemia, arrhythmia, congestive heart failure, sudden death or cardiovascular-related death) as serious adverse events associated with the use of varenicline.