BACKGROUND: Regardless of the intervention used, relapse after initial smoking cessation occurs in 70% to 80% of patients within 6 to 12 months. The investigators studied whether continuing bupropion treatment after initial success would decrease the relapse rate.
POPULATION STUDIED: The investigators enrolled 784 men and women, aged 18 years or older, who had smoked 15 cigarettes or more per day for the previous year. Participants were motivated to stop smoking and were generally in good health. The investigators excluded persons dependent on alcohol or other non-nicotine substances in the previous year, those using psychotropic medications or with a history of bupropion use, those currently using tobacco products other than cigarettes, and those currently using another therapy for smoking cessation.
STUDY DESIGN AND VALIDITY: This was a multi-center randomized double-blind placebo-controlled trial. All participants were given self-help material and took 300 mg bupropion sustained-release daily for 7 weeks. The subjects were instructed to set a target quit date 1 week after initiating treatment. Participants who had abstained from smoking cigarettes at week 7 were randomized to receive either bupropion or placebo for a total of 1 year. Allocation to treatment group was concealed and intention-to-treat analyses were performed. Participants returned for 14 visits during the first year (the medication phase) and for 5 visits during the follow-up year. All participants received the same educational material and counseling at each visit throughout the study.
OUTCOMES MEASURED: The study had 3 primary outcomes: (1) abstinence the week preceding each visit during the first year; (2) continuous abstinence during medication treatment; and (3) time to first relapse. Smoking status was defined by self-report of abstinence over the previous 7 days, confirmed with an expired air / carbon monoxide measurement at each visit. Relapse was defined by self-report, by expired air / carbon monoxide levels, or by missing 2 or more consecutive visits. Participants who were abstinent at every visit were classified as continuously abstinent.
RESULTS: Of the 784 participants enrolled in the open-label bupropion phase of the study, 461 (58.8%) were abstinent at week 7. Of these, 429 were randomized to receive placebo or bupropion for 45 weeks. A total of 347 (80.9%) remained in the study through the first year. Most participants (317, 73.9%) completed the entire 2 years of the study. Dropout rates were similar in the treated and untreated groups. At the end of 1 year, 55.1% of the treated patients were not smoking, compared with 42.3% in the placebo group (P= .001, NNT=8). At 18 months, significantly more treated patients were still not smoking (47.7% vs 37.7%, number needed to treat = 10). At the end of 2 years, however, abstinence rates were similar for the 2 groups (41.6% vs 40%). The drug was well tolerated. Insomnia and headache were the most common adverse effects.
Highly motivated patients who stop smoking during the standard 7-week bupropion program are likely to maintain abstinence as long as they continue to take the drug, at least for 1 year. Once they have discontinued the drug, however, the relapse rate in this group is the same as for those in the standard program. It is reasonable to offer bupropion indefinitely to certain patients who are able to quit smoking after the standard program—those who can afford it or perhaps those for whom another indication to take bupropion is identified—as long as the clinician informs them of the available data on relapse after they have ended their participation in the program.