LAUSR

BACKGROUND AND AIMS Level of adherence to tobacco cessation medication regimens is believed to be causally related to medication effectiveness. This study aimed to evaluate the efficacy of varenicline directly observed therapy (DOT) on varenicline adherence and smoking cessation rates among smokers with opioid use disorder (OUD) receiving methadone treatment. DESIGN Multicenter, parallel-group two-arm randomized controlled trial. SETTING Urban opioid treatment program (OTP) in the Bronx, New York, USA. PARTICIPANTS Daily smokers of ≥5 cigarettes/day, interested in quitting (ladder of change score 6-8), in methadone treatment for ≥3 months, attending OTP ≥3 days/week. Participants' mean age was 49 years, 56% were male, 44% Latino, 30% Black, and they smoked a median of 10 cigarettes/day. INTERVENTIONS Individual, block, random assignment to 12 weeks of varenicline, either directly observed with methadone (DOT, n=50) or via unsupervised self-administration (SAT, n=50). MEASUREMENTS The primary outcome was adherence measured by pill count. The secondary outcome was 7-day point prevalence tobacco abstinence verified by expired CO<8 parts per million. FINDINGS Retention at 24 weeks was 92%. Mean adherence was 78.5% (95% confidence interval (CI) 71.8-85.2%) in the DOT group versus 61.8% in the SAT group (95% CI 55.0-68.6%); differences were driven by DOT effects in the first 6 weeks. CO-verified abstinence did not differ between groups during the intervention (p=0.26), but was higher in the DOT than the SAT group at intervention end (DOT 18% versus SAT 10%, difference 8%, 95% CI -13, 28); this difference was not significant (p=0.39) and was not sustained at 24-week follow up. CONCLUSIONS Among daily smokers attending opioid treatment programs, opioid treatment program-based varenicline directly observed therapy was associated with early increases in varenicline adherence compared with self-administered treatment, but findings were inconclusive as to whether directly observed therapy was associated with a difference in tobacco abstinence.