To determine whether the predictive validity of the nicotine metabolite ratio is specific for transdermal nicotine therapy, another study evaluated this biomarker among 414 smokers in a 10-week placebo-controlled randomized trial of bupropion (Patterson et al. 2008). Faster metabolizers had significantly lower quit rates than slower metabolizers if treated with placebo, but had equivalent quit rates to slower metabolizers if treated with bupropion (Patterson et al. 2008). In a clinical trial of African-American light smokers, slower metabolizers based on the nicotine metabolite ratio had higher quit rates than faster metabolizers treated with nicotine gum or placebo (Ho et al. 2009).
