Effects of menthol on the pharmacokinetics of bupropion among Black smokers.

INTRODUCTION

Despite the widespread use of mentholated cigarettes, lower cessation rates, and disproportionately high smoking-related morbidity among Blacks, the possible role of menthol in smokers' response to pharmacotherapy has not been well-studied. This study examined the effects of menthol on the pharmacokinetic (PK) profiles of bupropion and its principal metabolites, hydroxybupropion, threohydrobupropion, and erythrohydrobupropion among Black smokers.

METHODS

After a 7-day placebo run-in period, participants received 150 mg bid sustained-release bupropion for 20-25 days. Blood samples were drawn for PK analysis on 2 occasions, 10-15 days after the commencement of bupropion while participants were still smoking (smoking phase) and at days 20-25 when they were asked not to smoke (nonsmoking phase).

RESULTS

18 smokers of nonmenthol cigarettes and 23 smokers of menthol cigarettes were enrolled in this study. No differences were found by menthol smoking status in the Cmax and area under the plasma concentration versus time curve (AUC) of bupropion and its metabolites in the smoking or nonsmoking phases. However, among menthol smokers, the AUC ratios of metabolite/bupropion were lower in the nonsmoking phase compared with the smoking phase (hydro/bup = 31.49 ± 18.84 vs. 22.95 ± 13.27, p = .04; erythro/bup = 1.99 ± 1.02 vs. 1.76 ± 0.75, p = .016; threo/bup = 11.77 ± 8.90 vs. 10.44 ± 5.63, p = .034). No significant differences were found in the metabolite/bup ratios between smoking and nonsmoking conditions among nonmenthol smokers.

CONCLUSIONS

We did not find a significant effect of menthol compared with nonmenthol cigarette smoking on the PKs of bupropion and metabolites at steady state. More research is needed to advance the understanding of mechanisms underlying disparities in smoking cessation outcomes related to smoking of menthol cigarettes.