Methadone Maintenance Treatment and Smoking Cessation

Inclusion Criteria: * Stable on methadone maintenance (an individual is considered 'stable' if they have had a 4 week constant/fixed dose of methadone by self report and verified by B.C. Pharmanet review) * Subjects must have smoked at least 10 cigarettes per day during the past year and over the month prior to the screening visit, with no period of abstinence greater than 3 months in the past year * Ages 19 to 75 years (inclusive) and motivated to quit smoking * Should read and understand English * For female subjects: * instructed and agrees to avoid pregnancy through 30 days after the last dose of study medication * has a negative urine pregnancy test at screening * agrees to use birth control method(s) for duration of the study * Should be available by telephone Exclusion Criteria: * Subjects who have used varenicline previously or are currently on other Nicotine Replacement Therapy or pharmacotherapy for smoking cessation (e.g., nicotine patch, zyban or wellbutrin) * Subjects who have a prior or current history of depression, bipolar affective disorder or a prior or current history of psychotic episodes or suicidal ideation (on the basis of self-report augmented by medical chart review where appropriate and/or corroborating history with previous or current health care provider) * Subjects who have not reached a stable dose of methadone in their methadone maintenance therapy (4 weeks at a constant/fixed dose of methadone by self-report and verified by B.C. Pharm…