Eight lab visits (V1 - V8) will be conducted during the 16 weeks following enrollment in the study. These visits will be largely identical, except that instructions and reminders to you about upcoming events will vary from session to session. At each lab visit the following will be collected: vitals (heart rate, blood pressure and weight); breath CO (Carbon Monoxide) and saliva samples for testing smoking and nicotine levels; and measures of smoking withdrawal and mood. You will be given daily diaries to record your smoking behavior and study medication. You will be given instructions on how and when to use all study materials. Advice on quitting and minimal support will be provided as requested at these visits. Each lab visit will require 20-30 minutes of your time.