Clinical Pharmacology of Nicotine: Implications for Understanding, Preventing, and Treating Tobacco Addiction

Department of Medicine, University of California, San Francisco, California, USA.
Clinical Pharmacology &#38 Therapeutics (Impact Factor: 7.9). 05/2008; 83(4):531-41. DOI: 10.1038/clpt.2008.3
Source: PubMed


Understanding the basic and clinical pharmacology of nicotine provides a basis for improved prevention and treatment of tobacco addiction. Nicotine acts on nicotinic cholinergic receptors in the brain to release dopamine and other neurotransmitters that sustain addiction. Neuroadaptation and tolerance involve changes in both nicotinic receptors and neural plasticity. Nicotine addiction can occur in the context of physical dependence characterized by self-medication to modulate negative affect and/or to relieve withdrawal symptoms, as well as, in light or occasional smokers, primarily for positive reinforcement in specific situations. Nicotine is metabolized primarily by CYP2A6. Its clearance exhibits considerable individual variability that is determined by genetic, racial, and hormonal (sex) factors. Genetically slow metabolism of nicotine appears to be associated with a lower level of dependence. Nicotine dependence is highly heritable and appears to be influenced by genes coding for some nicotine receptor subtypes, some neurotransmitter genes, and genes involved in neural connectivity. Novel pharmacotherapies for nicotine dependence include partial agonists for nicotinic receptors and nicotine vaccines. Pharmacogenetic studies suggest various candidate genes and a nicotine metabolism phenotype that influence outcome. Human pharmacology studies of nicotine and smoking behavior also provide a basis for assessing the benefits and risks of long-term nicotine use for harm reduction and for a potential cigarette regulatory strategy that includes reducing nicotine content of cigarettes to nonaddictive levels.

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    • "However, because NRTs appear to be more effective in suppressing tonic or background craving as opposed to phasic or peaks in craving (Ferguson and Shiffman, 2009; Schlagintweit et al., 2014), one might expect that NRTs would be most effective when smoking opportunities are not perceived to be imminently available. NRT effects are generally attributed to the pharmacological properties of nicotine (e.g., Benowitz, 2008; Stead et al., 2012); however, there is growing evidence that suggests that non-pharmacological factors make a substantial contribution (Caggiula et al., 2001; Dar and Barrett, 2014). Balanced placebo research, which crosses instructions regarding nicotine content (told nicotine-containing vs. told nicotine-free) with actual nicotine content (contains nicotine vs. no nicotine) suggests that the belief that nicotine has been consumed reduces cigarette craving and withdrawal regardless of whether or not nicotine was actually consumed (Dar and Barrett, 2014; Darredeau and Barrett, 2010; Gottlieb et al., 1987; Schlagintweit et al., 2014). "
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    • "While tobacco smoke contains ~4000 chemicals, of which ~250 are harmful, and ~50 are carcinogenic, nicotine itself is not a direct carcinogen [1] [21]. Nicotine may contribute to some smoking related diseases, but its contribution is generally considered much smaller than the tobacco combustion products, and NRTs do not increase the risk of cancer [22]. Notably, nicotine is contra-indicated in pregnant women because it may cause premature birth and in youths as it affects the developing brain [17]. "
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    ABSTRACT: There are a large number of smokers who want to quit smoking but have failed in their attempts to do so, with many having been unsuccessful at quitting multiple times over their lifetime. The existing marketed nicotine replacement therapies (NRT) have only marginal effectiveness and none provide a comparable physiological response to that derived from cigarette smoking; that is, rapid absorption of nicotine from the lung leading to peak levels of nicotine in the bloodstream to target the receptors in the brain. Instead, existing NRTs produce a slower and delayed rise in nicotine blood levels which is less effective at reducing the craving sensations. Published data for electronic cigarettes show that they typically deliver nicotine with a profile closer to that for nicotine patches, with a slow rise that can take 30 to 60 min, or longer, to reach the same peak nicotine concentration that is produced in less than 3 min from a single cigarette. A number of attempts have been made to develop an inhaled product which would deliver the nicotine through the lung and mimic the physiological response from smoking but many of them produced intolerable aversive reactions or delivered an ineffective dose. This paper discusses examples of the potential for the recent inhaled nicotine products in development to be effective as NRTs, but is not meant to be a comprehensive review.
    Full-text · Article · Aug 2015 · Asian Journal of Pharmaceutical Sciences
    • "Smoking is motivated and maintained by nicotine (Benowitz, 2008), but smoking and craving are also influenced by situational stimuli (Kozlowski and Herman, 1984). Surveys reliably link smoking and craving to cues such as presence of other smokers and drinking alcohol (McKennell, 1970; Russell et al., 1974). "
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    ABSTRACT: Laboratory cue reactivity (CR) assessments are used to assess smokers' responses to cues. Likewise, EMA recording is used to characterize real-world response to cues. Understanding the relationship between CR and EMA responses addresses the ecological validity of CR. In 190 daily smokers not currently quitting, craving and smoking responses to cues were assessed in laboratory CR and by real-world EMA recording. Separate CR sessions involved 5 smoking-relevant cues (smoking, alcohol, negative affect, positive affect, smoking prohibitions), and a neutral cue. Subjects used EMA to monitor smoking situations for 3 weeks, completing parallel situational assessments (presence of others smoking, alcohol consumption, negative affect, positive affect, and smoking prohibitions, plus current craving) in smoking and non-smoking occasions (averaging 70 and 60 occasions each). Analyses correlated CR craving and smoking cue responses with EMA craving and smoking correlations with similar cues. Although some cues did not show main effects on average craving or smoking, a wide range of individual differences in response to cues was apparent in both CR and EMA data, providing the necessary context to assess their relationship. Laboratory CR measures of cue response were not correlated with real-world cue responses assessed by EMA. The average correlation was 0.03; none exceeded 0.32. One of 40 correlations examined was significantly greater than 0. Laboratory CR measures do not correlate with EMA-assessed craving or smoking in response to cues, suggesting that CR measures are not accurate predictors of how smokers react to relevant stimuli in the real world. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    No preview · Article · Jul 2015 · Drug and alcohol dependence
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