Nicotine biomarkers and rate of nicotine metabolism among cigarette smokers taking buprenorphine for opioid dependency.

Background: Individual differences in the rate of nicotine metabolism contribute to differences in tobacco use, dependence, and efficacy of smoking cessation treatments and can be assessed using the nicotine metabolite ratio (NMR), a validated biomarker for CYP2A6 activity. Despite the high cigarette smoking rates observed in opioid users, no data have been reported on NMR among this population as they has been largely excluded from previous studies that have examined the relationship between tobacco use characteristics and rate of nicotine metabolism.

Methods: A linear regression model was used to examine the relationship between tobacco use characteristics and NMR among smokers taking buprenorphine for opioid dependency (N=141). The relationship between buprenorphine dose and NMR was also examined. All participants were enrolled in an intervention designed to promote cigarette-smoking cessation, though participants did not need to stop smoking to enroll.

Results And Conclusions: Rate of nicotine metabolism assessed using the NMR was positively associated with cigarettes smoked in the past 24h, but was not related to time to first cigarette or past year quit attempts. Dose of buprenorphine was not associated with NMR, suggesting no association with rate of nicotine metabolism. Our results suggest that NMR is related to tobacco use among persons enrolled in opioid treatment, as reported in general population smokers and may be a useful biomarker to include in future research assessing efficacy of tobacco cessation interventions in this population.