Participant Selection and Randomization
Participants aged 18 to 75 years who sought assistance with
smoking cessation, had smoked at least 10 cigarettes/d during
the previous year and the month prior to screening, and
had had no period of smoking abstinence longer than 3months
in the past yearwere eligible for the study.No financial incentives
were provided. Women of child-bearing potential were
allowed to enroll provided they agreed to avoid pregnancy
through 30 days after the last dose of study medication, had a
negative test for pregnancy (urinary β–human chorionic gonadotropin),
and agreed to use an effective birth control
method. Participants had to be prepared to attend clinic visits.
Only 1 participant per household was allowed. Exclusion
criteria are summarized in the Box.