Background: Smoking continues to be a major contributor to the burden of disease across the world although there has been a decrease in some developed countries such as USA and Australia. In countries of South-East Asia with a high prevalence of smoking, the incidence of tobacco-related diseases will continue to increase.
Methods: We reviewed the literature in relation to the pharmacology of nicotine, the measures used to determine the efficacy of anti-smoking therapies, and the randomised controlled trials and systematic reviews of pharmacotherapies published between 2004 and 2010. We focused primarily on the three first line therapies that are currently available: nicotine replacement therapy (NRT), bupropion and varenicline.
Results: Randomised controlled trials and meta-analyses have demonstrated that single therapy with either NRT, bupropion or varenicline are all more effective than placebo for smoking cessation. Abstinence rates for monotherapies varies from 13.3% to 19% for NRT compared to 7.5% to 14% for placebo, 19% to 19.7% for bupropion versus 10.9% to 11% for placebo and 25.5% to 25.6% for varenicline versus 11.2% to 14.8% for placebo. Of current therapies varenicline appears to be more effective at achieving abstinence. Some combination therapies with one or two formulations of NRT or NRT plus bupropion have demonstrated superior results to monotherapy. To date there are no randomised controlled trials of varenicline in combination with NRT or bupropion.
Conclusion: Further studies are required to address the uncertainty that exists on the most appropriate duration of therapy as well as the effectiveness and safety of combination pharmacotherapy. Post-marketing surveillance continues to play an important role in monitoring the adverse effects events associated with these therapies.