Varenicline and cardiovascular adverse events: a perspective review

Smoking is a leading preventable cause of mortality and morbidity. Varenicline, a first-line smoking cessation aid, is used widely to achieve successful quit rates in smokers. A number of studies and systematic reviews have evaluated the safety profile of the drug. To date, three systematic reviews by Singh and colleagues, Prochaska and Hilton, and Ware and colleagues, published between 2011 and 2013, have evaluated serious cardiovascular adverse events with varenicline use. Even though all three reviews demonstrated that serious cardiovascular adverse events were nominally more frequent in varenicline-treated patients when compared with placebo, a significantly increased event rate was found only in the review by Singh and colleagues. The three reviews included similar trials but differed in the evaluation of outcomes and performance of summary statistic computation. Though the evidence from the two most recent systematic reviews demonstrated that risk of serious cardiovascular events might not be increased with varenicline use, the US Food and Drug Administration has advised prescription with caution combined with close monitoring and education of patients until more conclusive evidence is available. Results of these reviews cannot be generalized to patients with unstable cardiac conditions.