Efficacy of Combining Varenicline and Naltrexone for Smoking Cessation and Drinking Reduction: A Randomized Clinical Trial.

Pharmacological treatments that can concomitantly address cigarette smoking and heavy drinking stand to improve health care delivery for these highly prevalent co-occurring conditions. This superiority trial compared the combination of varenicline and naltrexone against varenicline alone for smoking cessation and drinking reduction among heavy-drinking smokers. This was a phase 2 randomized double-blind clinical trial. Participants (N=165) who were daily smokers and drank heavily received either 2 mg/day of varenicline plus 50 mg/day of naltrexone or 2 mg/day of varenicline plus matched placebo pills for 12 weeks. Primary outcomes were 7-day point prevalence of nicotine abstinence (bioverified by a breath CO reading ≤5 ppm) at the 26-week follow-up and number of drinks per drinking day during the 12-week treatment phase. Smoking abstinence at week 26 was significantly higher in the varenicline plus placebo condition than in the varenicline plus naltrexone condition (N=37 [45.1%] compared with N=22 [26.5%]). For drinks per drinking day, there was a medication effect favoring the combination of varenicline and naltrexone over varenicline alone across the 12-week treatment phase, although it did not meet the significance threshold. These findings suggest that smoking cessation and drinking reduction can be concomitantly targeted with pharmacotherapy and that while varenicline alone may be sufficient as a smoking cessation aid in heavy-drinking smokers, the combination of varenicline and naltrexone may confer benefits with regard to drinking outcomes, particularly during the 12-week period of active medication treatment.