Aims
To test the efficacy and safety of varenicline as an aid to smoking cessation in methadone maintained smokers.
Design
Multicenter, randomized, double-blind, placebo-controlled trial with random assignment to 12 weeks of varenicline 1 mg twice daily (n=57) or matched placebo (n=55), with in-person and telephone counseling.
Setting
Urban methadone programmes in the Bronx, New York City, New York, USA.
Participants: Methadone maintenance patients, smoking ≥5 cigarettes/day, interested in quitting, stable in methadone treatment, without current axis I psychiatric disorders, suicidal ideation, or recent suicide attempts.
Measurements
Seven-day point prevalence abstinence verified by expired carbon monoxide (CO) < 8 p.p.m at week 12 (primary outcome); CO-verified abstinence, cigarettes/day, incident axis I psychiatric illness, suicidal ideation or serious adverse events (SAEs) at weeks 2, 4, 8, 12 or 24 (secondary outcomes).
Findings
Baseline demographic, smoking and clinical factors were similar between groups. Retention at 24 weeks was 90%. Subjects receiving varenicline were more likely than those receiving placebo to achieve abstinence (10.5% v 0%, p = .03; effect size 10.5%, 95% CI 4.4 – 19.3%) and to reduce smoking (median 5 v 2 cigarettes/day, p<.001) at 12 weeks. These effects were not maintained after drug treatment ceased. Incident psychiatric illness (OR = 0.84, 95% CI 0.16, 4.4) and suicidality (OR = 0.88, 95% CI 0.2, 3.9) were not different between groups. There were no psychiatric or cardiac SAEs.
Conclusions
Varenicline can aid short-term smoking abstinence in methadone maintained smokers.