Sustained-release bupropion has been shown to be an effective medication in persons who wish to stop smoking. Compared with placebo, patients receiving bupropion had a higher abstinence rate at the end of the medication phase and at one year. In addition, those treated with bupropion were more likely to abstain from smoking during the medication phase than those treated with placebo. There are no studies that examine which predictors of successful smoking cessation can be identified before using this medication to improve the likelihood of abstinence. Dale and associates attempted to identify predictors of smoking abstinence after bupropion therapy that could assist in the optimal use of this medication.

The study was a double-blind, placebo-controlled, dose-response trial performed at three sites in the United States. To qualify for the study, participants had to be smoking 15 or more cigarettes per day and be motivated to stop smoking. Participants completed multiple questionnaires concerning tobacco use and addiction and were then randomly assigned to receive sustained-release bupropion at 100, 150, or 300 mg per day, or placebo, for seven weeks and monitored for an additional 45 weeks. Demographic information, data on smoking history, smoking rates, and symptoms of nicotine withdrawal were collected during the medication phase. An expired carbon dioxide level of 10 ppm or less was used to confirm self-reported abstinence.

Six hundred and fifteen cigarette smokers participated in the study. At the end of one week, the abstinence rate was 44 percent among those taking the highest dose of bupropion. The higher the bupropion dose, the more likely participants were to be abstaining from cigarettes. Other predictors were male gender, length of abstinence from smoking with prior stop attempts and lower number of cigarettes per day. The study also found that more than 70 percent of the participants who were not smoking at the end of the second week maintained that abstinence during the medication phase.

The authors conclude that bupropion therapy is effective in a wide range of smokers who wish to quit. By using the above predictors, physicians can identify smokers who are more likely to fail bupropion therapy and provide them with additional smoking cessation strategies, such as longer and more aggressive counseling sessions or nicotine replacement therapy. The authors also noted that abstinence during the first two weeks of bupropion therapy is crucial. Physicians need to increase their support during this time by follow-up visits or telephone calls to maximize abstinence rates.