Clinical Research Directory

Inclusion Criteria: * adults aged 21 years or above * self-reported smoking at least 5 cigarettes/day for the past year with no intention to quit at time of screening visit * expired carbon monoxide level of more than 8 ppm at recruitment * willingness to participate in the proposed study, as indicated by signed informed consent * access to a functional telephone * expected presence in the study's geographical area for the next 4 months * not currently enrolled in any smoking cessation programs per self-report * female subjects of childbearing potential will be required to practice acceptable methods of birth control (the acceptable methods of birth control include birth control pills, Birth Control Shot, Birth Control Implant, Intrauterine Device \[IUD\], Diaphragm, and cervical cap) Exclusion Criteria: * history of active cancer (other than non-melanoma skin cancer) within the past 2 years * diagnosed with liver dysfunction or with previous liver diseases * levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, or total bilirubin over limit of normal range at prescreen * inability to refrain from acetaminophen, alcohol (no more than one drink daily via self-report) * are pregnant or nursing (lactating) or of childbearing age planning to become pregnant or unwilling to use adequate contraception during the study * participant answered "Yes" to any of the ASQ questions 1 through 3, or refuses to answer all of the questions. If subject answers 'Yes' to question 4 but the most recent suicide attempt took place more than12 months from screening visit then subject is still eligible.