BackgroundThis study is the first to examine longitudinal posttreatment outcomes of a placebo-controlled trial of varenicline for alcohol use disorder (AUD) with comorbid cigarette smoking. MethodsParticipants were 131 adults (n=39 female) seeking alcohol treatment in a randomized, double-blind, parallel group, placebo-controlled, 16-week multisite trial of varenicline combined with medical management (MM). Timeline follow-back assessments of alcohol and smoking behavior were conducted at the end of treatment (4months), with follow-ups at 6, 9, and 12months. Outcomes were percentage of heavy drinking days (PHDD), percent of participants with no heavy drinking days (NHDD), cotinine-confirmed prolonged smoking abstinence (PA), and good clinical outcome on either NHDD or PA. ResultsTreatment improvements were maintained posttreatment. For the sample overall, PHDD or NHDD did not differ significantly by treatment condition (ps>0.13), but varenicline produced higher rates of PA versus placebo at 4, 9, and 12months (p<0.05). Significant differences were observed by sex: Males had higher rates of NHDD with varenicline (28.9%) versus placebo (6.4%) at the end of treatment (p=0.004), and these effects were maintained at 12months (varenicline: 40.0% vs. placebo: 19.2%, p=0.03). Higher rates of PA were seen for varenicline in both males (8.9%) and females (21.1%) versus placebo (males/females: 0%) at the end of treatment (p=0.05), and this effect was maintained at 12months for females (varenicline: 21.1% vs. placebo, 0.0%, p=0.05). ConclusionsVarenicline treatment combined with MM appears to have enduring benefits for patients with co-occurring AUD and cigarette smoking, and these effects may differ by sex.