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Smoking cessation

Tobacco dependence continues to be a major health hazard and because smoking may pose a health risk for non-smokers as well, smoking cessation treatments are of great public interest. Although cigarette packs are printed with warnings concerning the possible health risks of smoking, laws have been passed to confine smokers to particular public areas, and aversion to second hand smoke has been made well-known through a great amount of publicity, many people who want to quit smoking for health and aesthetic reasons still find themselves unable to do so. The combustion of tobacco produces poisons and carcinogens that present a significant health hazard for smokers and non-smokers alike. Nicotine is a principal component of tobacco, and the most pharmacologically active. It is physically addictive, making it extremely difficult for a smoker to quit. Smoking a cigarette delivers nicotine vapors to the lungs, where nicotine is rapidly absorbed through the arteries and delivered to the brain. Nicotine interacts with nicotine cholinergic receptors in the brain to induce the release of neurotransmitters and produce an immediate reward that is associated with a rapid rise in blood level. A persistent stimulus is also produced, and is associated with a high blood level of nicotine. As such, the dopaminergic reward system is activated which eventually results in nicotine dependency. Nicotine can produce a myriad of behavioral effects and is unquestionably one of the most popular and powerful reinforcing agents. Nicotine induces changes in the number of nicotinic cholinergic receptors and this is one possible mechanism underlying tolerance. Besides its main direct action at nicotinic cholinergic receptor sites, through linkage of these sites with other neurotransmitter systems, nicotine has indirect effects on the release of most of the known neurotransmitters. Through its action on the locus coeruleus it has a widespread effect on noradrenergic activity throughout the brain. It also activates ascending dopaminergic pathways thought to be involved with the brainstem and hypothalamic reward systems. For health and other reasons, large numbers of cigarette smokers are trying to stop smoking. A therapeutic approach to aid in smoking cessation is to provide the smoker with nicotine from sources other than cigarettes. Nicotine replacement therapy as an aid to quitting smoking has been become increasingly popular. Nicotine chewing gum and transdermal nicotine are two of the more popular forms of nicotine replacement available commercially. Withdrawal from nicotine following chronic use of tobacco products results in the emergence of an abstinence syndrome which reaches its peak intensity within the first day. Cessation of smoking has been shown to result in a number of signs and symptoms of withdrawal such as increases in irritability, anxiety, restlessness, impatience, somatic complaints, cigarette craving, hunger, insomnia, tremulousness and heart rate as well as difficulty concentrating, all of which are collectively called the tobacco withdrawal syndrome.

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