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Clinical Pharmacology of Electronic Cigarettes

Principal Investigator: Neal Benowitz

Funding Mechanism: National Institutes of Health - Grant

ID number: 1 R01 DA039264-01

Award Date: 5/5/2015

Institution: University of California, San Francisco

Electronic cigarettes (e-cigarettes) are growing in popularity. However, their potential addictiveness and safety of use are unknown. The goal of this study is to evaluate e-cigarettes by assessing key factors associated with nicotine addiction and possible health effects. Specific aims are: (1) to characterize nicotine delivery, systemic exposure and effects following e-cigarette use; (2) to assess the possible health effects of e-cigarette use; and (3) to validate biomarkers to distinguish e-cigarette use from traditional cigarette use.  In this two-week study, 36 dual e-cigarette/traditional cigarette users (ages 18 and older) will switch between the two product types, each to be used exclusively for one week. During each week, subjects’ use and subjective assessments will be tracked for four days as outpatients followed by three days on a research ward. To address Aim 1, researchers will gather information related to the fraction of nicotine inhaled from e-cigarettes that is retained in the body and how retention is influenced by device type, e-liquid nicotine, propylene glycol and glycerin concentrations, e-liquid pH, e-liquid flavor, and battery voltage. Researchers will also evaluate users’ systemic exposure to nicotine and the amount of nicotine exhaled, and how these relate to e-cigarette product characteristics. Finally, researchers will compare e-cigarette and traditional cigarette use with regard to time to peak nicotine concentration; daily intake of nicotine; satisfaction, reward, craving and withdrawal symptoms; and puff patterns.  To address Aim 2, researchers will compare dual use, e-cigarette use alone, traditional cigarette use alone, and no product use with regard to levels of exposure to tobacco smoke toxicants (particularly volatile organic compounds) and cardiovascular effects. To address Aim 3, researchers will evaluate whether the ratio of nicotelline to nicotine metabolites (cotinine or total nicotine equivalents) in urine distinguishes e-cigarette use from traditional cigarette use.  Findings may inform regulatory activities related to e-cigarettes.