According to new research published online in the American Journal of Respiratory and Critical Care Medicine, the smoking cessation drug Chantix (varenicline) may put users at higher risk for a cardiovascular event.
In “Cardiovascular and Neuropsychiatric Events Following Varenicline Use for Smoking Cessation,” researchers in Canada report that in an observational, self-controlled trial, patients prescribed varenicline (Chantix in the US; Champix in Canada and Europe) were 34% more likely to have an emergency department visit or hospitalization for a cardiovascular event while taking the drug. Among those patients who had not previously experienced a cardiovascular event, the increased incidence was only 12%.
The researchers estimated that among all patients, there were 3.95 adverse cardiovascular events per 1,000 varenicline users that could be attributed to the drug. “This is a figure that physicians can quote to their patients,” the authors wrote.
The researchers also found a small increase in emergency department visits and hospitalizations for neuropsychiatric symptoms, but they wrote the findings were not robust and did not appear to be clinically meaningful.
“Previous studies regarding the safety of varenicline have been conflicting and most examined people with relatively similar characteristics and backgrounds in highly controlled settings,” said lead study author Andrea S. Gershon, MD, an associate professor of medicine at the University of Toronto and a scientist at the Institute for Clinical Evaluative Sciences and Sunnybrook Health Sciences Centre in Ontario, Canada. “We wanted to study varenicline among all kinds of people in the real world.”
The researchers analyzed the medical records of 56,851 new users of varenicline between Sept. 2011 and Feb. 2015 living in Ontario. The records were studied from a year prior to the year following the date when varenicline was prescribed. During that time, 4,185 and 4,720 patients experienced one or more cardiovascular or neuropsychiatric events, respectively, that resulted in an ER visit or hospitalization.
Because the study is observational, it cannot determine cause and effect. The authors said the study was limited by a number of other factors, including not having information about whether the patients quit smoking, whether they took other medications to help quit smoking and whether nicotine withdrawal accounted for some of the neuropsychiatric events reported.