Effectiveness of GW468816, an NMDA Glycine Site Antagonist, for Prevention of Relapse to Smoking

The purpose of this study is to evaluate the efficacy of the glycine antagonist, GW468816, compared with placebo on duration of abstinence and rates of relapse in recently quit female smokers in a randomized, double-blind, five-week clinical trial. According to the investigators, the new medication, GW468816, is thought to send certain signals in the brain that may be effective in helping people stay abstinent after they have recently quit smoking. GW468816 is a non-nicotine drug. The investigators of this study hypothesize that subjects receiving GW468816 will demonstrate a significantly longer time to relapse to smoking than those in the placebo group, as measured by the primary outcome measure (see below).