The public health burden of smoking is so enormous it is not surprising that varenicline—the most recently approved drug for smoking cessation—has been prescribed so widely and discussed extensively. A linked paper by Svanström and colleagues (doi:10.1136/bmj.e7176) further explores the association between use of varenicline and the occurrence of serious cardiovascular events, including myocardial infarction, unstable angina, ischaemic stroke, and death from cardiovascular disease.1

Varenicline (Champix, Chantix) was approved by the Food and Drug Administration (FDA) in May 2006, and from that date until July 2011 about 8.9 million patients received 21.8 million prescriptions for this drug from outpatient retail pharmacies in the United States.2 Widespread prescribing of varenicline has also occurred elsewhere. In New Zealand, for example, its use increased steadily (to about 13 000 patients) during the first three years of marketing and then doubled in the fourth year (to almost 24 000 patients) after subsidisation by the government’s pharmaceutical management agency (unpublished data from New Zealand Intensive Medicines Monitoring Programme).

Against this background of increasing worldwide use of varenicline, postmarketing surveillance and other research have identified and investigated several safety concerns. Reported adverse effects of varenicline include psychiatric effects,3 4 suicide and suicidal ideation, …