Smoking cessation pharmacology

Annals of the American Psychotherapy Association, Fall, 2007 by Harpriya A. Bhagar, Alan D. Schmetzer

Approximately 400,000 Americans die each year from the effects or consequences of cigarette smoking. Smoking increases the risk of lung cancer 22 times in men and 12 times in women. Between 1960 and 1990, deaths from lung cancer in women increased 400%, and by the mid1980s they surpassed deaths from breast cancer in women. Further, exposure to second-hand smoke causes an estimated 3,000 deaths annually (Centers for Disease Control and Prevention, 2006). Despite these alarming trends, the national prevalence of smoking in 2004 still averaged about 22% percent of the population (United Health Foundation, 2006). What is the mystery behind this highly prevalent and dangerous addiction? Like all addictions, there are certain biological, psychological, and social reinforcements. Hence, successful treatment must address all of these aspects.

From a pharmacological perspective, Nicotine Replacement Therapies (NRTs) and bupropion, a nicotine-free alternative, are considered first-line smoking cessation therapies. Other nicotine-free alternatives, like nortriptyline and clonidine, are considered second-line treatment options (Fiore et al., 2000). In 2006, the U.S. Food and Drug Administration approved varenicline tartrate, also a nicotine-free medication, for smoking cessation (Anthenelli, 2007). Further, non-pharmacological measures are equally important in assisting with abstinence from smoking. Recently, a 4-month health-promotion/health-protection intervention of smoking cessation at a labor union apprenticeship program demonstrated a 19.4% post-intervention quitrate at 1 month among baseline smokers (Barbeau et al., 2006). In addition, social and political influences like banning smoking in public places are efforts to minimize exposure to second-hand smoking.

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In a study comparing the efficacy of NRTs, bupropion, and nortriptyline, NRTs were the most successful monotherapies, with an efficacy rate of 500/o (Flora, Emiliano, & Coelho, 2005). An NRT is used to gradually wean the patient from the influence of nicotine. The cost is about the same or less than that of cigarettes. NRTs are available as patches, gums, inhalers, and nasal (nose) sprays. Nicotine patches are usually dispensed as 14-21 mg/day for 4 weeks, and then as 7-14 mg/day for 4 weeks. The patch is changed daily, and the application site should be rotated to reduce skin irritation. Nicotine gum is available in strengths of 2 mg or 4 mg and it should be chewed for 1-2 hours over a period of 1-3 months for best results. The gum may cause hiccups, stomach upset, or sore jaw (American Academy of Family Physicians, 2007). NicotrolTM inhaler is a cartridge system that can be orally inhaled when there is a craving to smoke. It may satisfy some of the oral fixation occurring with cigarette use, as well as the nicotine addiction. Not more than 16 cartridges a day should be used and the length of treatment should be held to no more than 12 weeks. It can irritate the mouth and throat and cause cough (American Academy of Family Physicians, 2007). Nicotine nasal spray is applied as 1-2 sprays to each nostril. One spray to each nostril constitutes a "dose." The Agency for Health Care Policy and Research recommends a maximum of 5 doses per hour, or 40 doses per day. It can cause nasal irritation, diarrhea, and tachycardia.

Patients should not smoke while using NRTs. Cases of death from cardiac failure have been reported with multiple doses of nicotine patches, along with concomitant smoking and alcohol consumption ("Nicotine patch," 2007). In case of pregnancy or cardiac or blood vessel disease, a consultation with a physician regarding risks-versus-benefits should be conducted prior to using an NRT (American Academy of Family Physicians, 2007).

Bupropion has been used as an anti-depressant since 1989. It was licensed for use in smoking cessation in 1997 and marketed under the trade name of ZybanTM (bupropion sustained release) at 150 rag. Its main mechanism is believed to be via dopamine and noradrenaline reuptake inhibition. This formulation has been extensively evaluated for smoking cessation and has shown continuous abstinence rates of 20% at 1 year across many clinical groups. It is well tolerated, but does have side-effects like insomnia, headache, dry mouth, dizziness, and nausea. It is a cytochrome P450 2D6 inhibitor and care must be taken when co-prescribing other medicines that are metabolized by this enzymatic pathway (Wilkes, 2006). It is contra-indicated in people who have seizure disorders and current or past history of bulimia or anorexia (Kline, 2007).

Varenicline (ChantixTM) is a partial nicotinic acetylcholine receptor agonist. It is dosed as 0.5 mg daily for 3 days, then 0.5 mg twice daily for 4 days, then 1 mg twice daily for 11 weeks. It is strongly recommended that patients identify a target "quit date" to coincide with the initiation of the 1 mg twice-a-day-dose. Patients who are successful are continued on Chantix for another 12 weeks to reduce relapse. Nausea, vomiting, constipation, flatulence, and sleep disturbance are reported as common side effects (Anthenelli, 2007). Four placebo-controlled trials showed that after 12 weeks of treatment with varenicline, 22% of the patients remained abstinent at 1 year, versus 8% of those who were treated with a placebo ("Varenicline," 2006). Varenicline was also associated with higher short- and long-term abstinence rates compared with bupropion SR, although in one study, the comparison with bupropion SR was not statistically significant for weeks 9 through 52 (Anthenelli). Currently, no comparison studies between varenicline and NRTs are available ("Varenidine"). However, clinicians feel that varenicline might have a better long-term quit-rate and a more tolerable side-effect profile than NRTs.