Varenicline shown to help 'quit smoking'

A drug recently approved by the U.S. Food and Drug Administration as an aid to smoking cessation appears effective both short- and long-term for smokers trying to quit, according to two reports in the August 14/28 issue of the Archives of Internal Medicine.

Smoking is the leading cause of preventable death in the United States and worldwide. Currently available pharmacotherapies for smoking cessation include nicotine replacement therapy (NRT)--such as gum, skin patches, tablets, nasal spray and inhalers--and the antidepressant drugs bupropion hydrochloride and nortriptyline hydrochloride. These have shown limited success rates, with success at one year averaging approximately seven percent to 30 percent, according to background information in the articles.

The new drug varenicline tartrate mimics the effects of nicotine to help offset cravings, and in the presence of nicotine it helps suppress some of the reinforcing effects of smoking.

Mitchell Nides, Ph.D., of Los Angeles Clinical Trials, and colleagues with the Varenicline Study Group conducted a randomized, double-blind, placebo-controlled study to evaluate the efficacy, tolerability and safety of varenicline for smoking cessation. Healthy smokers aged 18 to 65 years were randomly assigned to receive varenicline in a dosage of .3 milligrams once daily, 1 milligram once daily, or 1 milligram twice daily for six weeks, plus placebo for one week; to 150 milligrams of sustained-release bupropion hydrochloride twice daily for seven weeks; or to placebo for seven weeks.

The authors report that varenicline, in combination with brief behavioral counseling, was more effective for short- and long-term smoking cessation than placebo.

"Efficacy improved as the dose increased, with varenicline tartrate, 1 milligram twice daily, providing the highest rates of continuous abstinence across all treatment groups, including bupropion," they write. Four-week continuous quit rates were 48 percent for varenicline, 1 milligram twice daily; 37.3 percent for varenicline, 1 milligram daily; 33.3 percent for bupropion hydrochloride; and 17.1 percent for placebo. Long-term quit rates from four weeks to one year were 14.4 percent for the group that received varenicline, 1 milligram twice daily, vs. 4.9 percent for placebo.

"In this study, varenicline tartrate, 1 milligram twice daily, effectively helped subjects quit smoking, with response rates three times higher than those for placebo while demonstrating a good tolerability profile in this population of smokers who on average had smoked approximately 20 cigarettes per day for approximately 24 years," the authors write. "Efficacy was maintained in the non-drug treatment phase through week 52. The significant reductions in craving and in some of the rewarding effects of smoking seen with varenicline tartrate, 1 milligram twice daily, may assist in promoting abstinence and preventing relapse," they conclude.