In 2021, varenicline, the most effective single drug for quitting smoking, was withdrawn from the market in the UK because impurities were found at greater levels than is considered safe.
Rapidly, varenicline (then sold under its brand names, Champix and Chantix) became unavailable. This was a disaster for public health. Research from University College London estimated that varenicline being unavailable resulted in about 1,890 more avoidable deaths each year because fewer people were successfully quitting smoking.
