Effect of varenicline directly observed therapy versus varenicline self-administered therapy on varenicline adherence and smoking cessation in methadone-maintained smokers: a randomized controlled trial.

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.