A series of studies from Norway using the experimental drug varenicline showed promise for smoking cessation. This partial agonist of the alpha-4-beta-2 nicotinic receptor aided smokers in quitting the habit by the end of 12 weeks of treatment. Importantly, it also aided in maintaining abstinence through one year.

Two nearly identical varenicline studies with more than 1,000 patients each showed those taking the drug were approximately twice as likely to quit smoking after 12 weeks compared with those taking buproprion. Those taking varenicline were also approximately four times as likely to quit smoking as those on placebo.

All study subjects smoked at least 10 cigarettes per day, with most being pack-a-day users, said lead author Serena Torstad, M. D., Ph. D., University of Oslo, Norway. Carbon monoxide measured in breath tests confirmed the quit rates.

A third, open-label maintenance study randomized 1,206 patients who had quit at the end of 12 weeks on varenicline to an additional 12 weeks. The continuous abstinence rate for one year for patients taking 24 weeks of varenicline was 70.6 percent, compared with 49.8 percent who had received only six weeks of treatment (p = <0.0001).