Nicotine: Cotinine levels in blood during cessation of smoking

Abstract

HE ROLE OF NICOTINE as a primary reinforcer and of nicotine withdrawal as a factor in maintaining cigarette smoking behavior has been recently reviewed by Jarvik. ~ In this paper, we present an exploration of the relationship between the amount of nicotine in cigarettes smoked per day, serum cotinine levels, and difficulty in modifying the smoking habit. Cotinine is the major nicotine metabolite. In contrast to the short half-life of nicotine itself, the half-life of cotinine in blood is far longer (30 hr versus 30 rain, respectively). Furthermore, cotinine is usually found in the blood at levels greater than that of nicotine, 2-s and cotinine levels remain fairly constant in individuals who smoke according to a consistent pattern. 2.4.r On this basis, we felt that serum levels of cotinine would be a better index of the degree of chronic nicotinism than measures of the parent alkaloid. Cotinine is approximately 50 times less toxic than nicotine in rats. s-lo In this study, participants in a smoking cessation program were asked to rate themselves in terms of the difficulty they experienced in giving up smoking. They also provided information on the number and type of cigarettes they had been smoking. We then examined the correlations between this information provided by the participants, their success in stopping cigarette use, and serum c0tinine levels taken at several points during the course of the participaIion in the cessation program. In addition, we attempted to ascertain activity of the sympathetic system by measuring plasma dopamine-beta-hydroxylase (DBH).