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Bupropion for Smoking Cessation

Background: Buproprion hydrochloride is recommended for smoking cessation; however there have been relatively few clinical studies examining the efficacy of bupropion.

Objective: The purpose of the study was to confirm and expand the results of previous studies that have examined the efficacy of bupropion for smoking cessation.

Methods: This was a randomized, double blind placebo controlled study that took place between September 1998 and March 2001. Patients who reported to be current smokers were included in the study. This study excluded patients with; contraindications to bupropion or nicotine replacement therapy, major serious psychiatric illnesses, a recent history of alcohol abuse in the past 3 months or consumption of more than 3 alcoholic beverages per day. 244 patients consisting of 210 males and 34 females who were 20 years or older participated in the study. The treatment group consisted of 121 patients receiving bupropion 150 mg BID for 7 weeks and 123 patients receiving placebo. Both groups also received nicotine replacement therapy and cognitive behavioral therapy. Five follow-up phone counseling calls were placed on the first week, third week, and then monthly for the first three months. An intention to treat and per protocol analysis were used to analyze the data. The Beck Depressive Inventory was used to assess depressive syptomatology and the Fragerstrom Tolerance Questionnaire was used to determine the level of nicotine dependence. 2 tailed p-values <0.05 were considered to be statistically significant.

Results: In the intention to treat analysis, 75% of the patients reported quitting at the assigned quit date and 81% after 1 week follow-up. There was no difference in self-reported smoking cessation. At 3 weeks of follow-up, the Relative Risk (95% CI) was 1.02 (0.88-1.17) (p > 0.82). At 7 weeks, quit rates were 64% in the bupropion group and 57% in the placebo group, RR = 1.13 (0.92-1.39) (p = 0.23). At 4-5 weeks after that, the difference in quit rate was 57% in the bupropion group versus 47% in the placebo group, RR = 1.21 (0.95-1.34) (p = 0.12). At 6 and 12 months, the quit rates for both groups were similar. Patients in the bupropion group had significantly fewer withdrawal symptoms at 1 week (p = 0.04) and 8 weeks (p = 0.08) of follow-up. Validation of quitting using saliva cotinine levels or spousal proxy was 22% in the bupropion group versus 28% in the placebo group (p = 0.31). The median number of quit attempts was 3.6 for the bupropion group and 3.1 for placebo (p = 0.74). Quitters gained more weight than the nonquitters (p = 0.41) and there was no difference in weight gain between the two groups (p = 0.90). African Americans, married participants and patients with a history of alcohol abuse all had increased odds of smoking cessation. Patients with an increased level of nicotine dependence had decreased odds of smoking cessation. The per protocol analysis was performed on patients who were 80% compliant in taking the study medication. Compliant patients had average similar quit rates at 1 week and 3 weeks of follow-up. Quit rates at the end of 7 weeks was 82% for the bupropion group versus 73% for the placebo group (p = 0.24). At 6 months, the quit rates were 49% for bupropion and 53% for the placebo group (p = 0.63). Finally, at 1 year, the quit rates were 33% for the bupropion group and 27% for the placebo group (p = 0.48).

Strengths: This was a randomized double blind, placebo controlled study. The authors did not have any financial ties to the manufacturer of the study drug. Final quit rates were assessed using saliva cotinine tests when possible.

Weaknesses: For this study, participants were recruited from previous smoking cessation study enrollees, which may have led patients to be more resistant to quitting. Type II error may have been a possibility in this study because of the relatively low number of patients, the absence of reported power and the large differences that existed between various aspects of the study results. The study population was limited to middle aged white males who were smokers, which may not be representative of the population as a whole. A large number of participants were able to guess which group they were in and though it was considered to be not statistically significant, there was a large percentage difference between the two groups. Compliance was measured on a self report basis. Therefore, the reported compliance may not be accurate. The study may have been too short to determine if there was a detectable or sustainable difference in quit rates. A lot of the data collection methods were self reported and this could have led to bias. Finally, the study focused only on long term heavy smokers which made the study limited in scope.

Conclusion: I believe that this study could have been designed better. It was appropriate to use a double blind randomized controlled placebo study, but there are several problems associated with the study. Patient compliance was a significant issue because the results might have been different if compliance was better controlled by the investigators. There could have been a larger number of people in the study (including more women to be more representative of the population as a whole) to reduce the possibility of Type II error. The study did not fulfill the study objective because it did not show that bupropion is more effective than placebo for smoking cessation. The weaknesses of this study can be addressed and stronger future studies could be developed to provide more reliable information on the effectiveness of using bupropion for smoking cessation.

Simon JA, Duncan C, Carmody TP, Hudes ES. Bupropion for smoking cessation: A randomized trial. Arch Intern Med 2004 Sept 13;164:1797-1803.

Sekhar Mamidi, Pharm.D. Candidate