Chapter 8 
nicotine metabolite, has a half-life of about 20 hours (Cummings and 
Richard, 1988; Jarvis, 1989; Jarvis et al., 1987) and therefore persists in the 
body even longer. 
It is difficult to disrupt these patterns when people have access to 
cigarettes. In a study by Benowitz and colleagues (1986a), people switched 
from 30 to 5 cigarettes per day. Because they tended to smoke these 
5 cigarettes much more intensely, they reduced carbon monoxide levels 
by only one-half and nicotine levels by only about one-third. Thus, nicotine 
intake remained high enough to sustain dependence. 
After quitting smoking, most people relapse quickly, and about one-third 
of the people who have quit smoking and remained abstinent for 1 year 
relapse (Fiore, 1992). As with alcohol and heroin, most nicotine relapses 
occur during the first 3 months of abstinence (Hunt et al., 1971). In fact, the 
determinants of relapse (e.g., degree of dependence and negative emotional 
states) and remission (e.g., substance-associated health problems and learning 
to manage cravings) are also similar across these three classes of drug 
dependence (U.S. Department of Health and Human Services, 1988). 
Relapse to nicotine dependence has been studied in greater detail than 
relapse to heroin, cocaine, and alcohol dependence. Data from a Mayo Clinic 
study showed that, with minimal treatment intervention, one-quarter of the 
people relapsed in 2 days and about one-half in the first week (Kottke et al., 
1989). More recent data on people who quit on their own showed that about 
two-thirds relapse within 3 days (Hughes et al., 1992). The withdrawal 
syndrome can be debilitating in its own right, but in the long run, its worst 
health consequences may be that most efforts to quit smoking never survive 
the withdrawal phase (Hughes et al., 1992), thereby dooming one-half of 
persistent smokers to die prematurely because of their tobacco use (Peto et al., 
1994). Much of the benefit of current nicotine medications is providing 
adequate nicotine replacement for that formerly provided by cigarettes to 
help more people remain nonsmokers during the important first few weeks 
of tobacco abstinence. 
NICOTINE Tobacco products come in many different forms. All have toxicities and 
DELIVERY dependence potential, and there is variation related to the type of tobacco 
SYSTEMS product and route of administration. Although the focus here is on 
cigarettes, at some point similar issues must be addressed with other tobacco 
products that currently have no dosage labeling. For example, moist snuff 
products vary widely in their nicotine-dosing capabilities, and there is 
evidence that the variation is accomplished primarily by manipulation 
of the pH level of the products by tobacco manufacturers (Henningfield 
et al., 1995; Djordjevic et al., 1995), but neither tobacco companies nor 
governmental agencies provide any form of nicotine dosage information 
to consumers except in cigarette advertising. 
The cigarette, which may be conceived of as a nicotine dispenser with 
smoke as the vehicle, is the most toxic and dependence-producing form of 
nicotine delivery. Nicotine is volatilized at the tip of a burning cigarette from 
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