NCT01627392

Mechanisms of the Nicotine Metabolism Effect on Tobacco Dependence

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 305 (actual)
• Sponsor: University of California, San Francisco · Academic / Other
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: Accepted

Summary

The purpose of the study is to learn more about tobacco dependence and nicotine metabolism in African-Americans and whites, by studying to see if how fast a person metabolizes nicotine (how the body breaks down nicotine into inactive compounds) affects how dependent they are on smoking cigarettes. The investigators believe that people with a faster rate of metabolism may have more severe nicotine withdrawal symptoms and also may have a harder time trying to quit smoking.

Detailed description

Our studies will use the nicotine metabolite ratio (NMR) (the ratio between the nicotine metabolites 3'hydroxycotinine and cotinine)as a simple and clinically feasible biomarker for the rate of nicotine metabolism. The investigators hypothesize that a faster rate of metabolism leads to faster elimination of nicotine from the body and a more rapid dissipation of brain tolerance to nicotine in the interval between cigarettes, leading in turn to (1) more severe nicotine withdrawal symptoms and (2) greater subjective reward from the cigarette smoked following deprivation. These effects would help to explain why smokers with faster rates of nicotine metabolism have a poorer response to smoking cessation therapy when compared to those with slower rates of metabolism. The investigators will explore the relationship of the NMR to the endophenotypes of withdrawal, craving and reward, with the assumption that these factors are likely intermediaries for the mechanism linking nicotine metabolism to tobacco dependence and smoking cessation rates with pharmacotherapy. Our study design uses a brief (6 hour) interval of smoking abstinence followed by a "reward" cigarette to elicit the subjective responses relating to withdrawal and reward. Because smoking behavior and severity of nicotine dependence vary by race and sex the investigators will also compare the relationship between NMR and withdrawal and reward in African American vs white smokers and in men vs women. Secondary analyses will examine whether nicotine half-life mediates the observed effects of NMR on primary response measures.

Conditions

• Cigarette Smoking

Interventions

Type	Name	Description
BEHAVIORAL	Smoking abstinence	6 hour smoking abstinence

Timeline

• Start date: 2012-07-01
• Primary completion: 2015-08-01
• Completion: 2015-08-01
• First posted: 2012-06-25
• Last updated: 2015-12-03

Locations

1 site across 1 country: United States