Varenicline for smoking cessation among methadone-maintained smokers: a randomized clinical trial

With smoking rates far exceeding the general population, methadone-maintained (MMT) opiate-dependent smokers experience high rates of tobacco-related health consequences. Previous treatment studies have used nicotine replacement and produced low quit rates.

We test, using a three-group randomized design, the efficacy of varenicline versus placebo, in comparison with nicotine replacement therapy (NRT) that combines nicotine patch prescription plus ad libitum nicotine rescue, for smoking cessation. We recruited methadone-maintained smokers from nine treatment centers in southern New England and provided six months of treatment, and a minimal behavioral intervention at baseline (NCI's 5A's). Outcomes included carbon monoxide (CO) confirmed 7-day point smoking cessation prevalence at 6 months and self-reported change in mean cigarettes per day.

The 315 participants had a mean age of 40, with 50% male and 79% non-Hispanic White, smoked an average of 19.6 (± 10.4) cigarettes/day, and had a mean daily methadone dose of 109 mg. Intent-to-treat analyses, with missing considered to be smoking, showed the rate of CO-confirmed 7-day abstinence at 6-months was 5.4% overall, with varenicline 3.7% compared to placebo 2.2%, and NRT 8.3% (p>.05). Adherence rates during the 7-days immediately prior to 6-month assessment were 34.2% in varenicline, 34.4% in placebo, and 48.8% in NRT. Between baseline and 6-months there was an overall self-reported mean reduction of 8.3 cigarettes/day.

Varenicline did not increase quit rates over placebo. Smoking cessation rates in methadone-maintained smokers are low and novel treatment strategies are required.