A number of other tobacco cessation therapies are available or in development.137,138 Cytisine, a naturally occurring substance chemically related to varenicline, has been used for smoking cessation for decades in parts of Eastern Europe. In a Cochrane meta-analysis of two recent trials comparing cytisine with placebo, the risk ratio for cessation was 3.98 (95% confidence interval 2.01 to 7.87).96
Also in development are antinicotine vaccines. The rationale for immunisation against nicotine is to induce antibodies that bind nicotine in the blood, thereby preventing it from crossing the blood–brain barrier. It is postulated that with less nicotine reaching the brain immediately after smoking, the vicious cycle between smoking and nicotine-related gratification will be broken. Phase II studies have evaluated three different vaccines, NicVAX®, Nicotine-Qbeta™ and TA-NIC. While some results from these small studies are promising, the NicVAX data are disappointing. The vaccines need to be administered regularly to maintain effects – they will not provide long-term protection with a single course of treatment. Larger ongoing studies of a longer acting vaccine are needed before this approach can be evaluated.139,140
Given that the current available first line medications are all efficacious, and non-drug factors make a substantial contribution to the likelihood of quitting successfully,110 choice should be based on overall evidence of relative efficacy, clinical suitability and patient preference (see Figure 2. Pharmacotherapy treatment algorithm page 29).
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- Hall W, Gartner C. Ethical and policy issues in using vaccines to treat and prevent cocaine and nicotine dependence. Curr Opin Psychiatry 2011 Mar 22. [Epub ahead of print].