An estimated 70 percent of persons who smoke have a desire to quit completely. Smoking is the primary preventable cause of morbidity and mortality in the United States. Therefore, physicians should get involved in encouraging and facilitating smoking cessation. Studies have shown that even brief advice from physicians has a positive effect on cessation efforts. Pharmacologic treatment to support smoking cessation increases the likelihood of success, and the effectiveness of these medications is further increased by behavior therapy. Corelli and Hudmon reviewed the medications approved by the U.S. Food and Drug Administration (FDA) for smoking cessation.
Currently, four nicotine replacement therapies (NRT) are available, plus sustained-release bupropion. The use of NRT increases cessation success rates by reducing nicotine withdrawal symptoms. Because the release of nicotine into the system is slower with these medications than with smoking alone, patients are weaned from the immediate effects of inhaled nicotine. NRT should be avoided in patients with serious arrhythmias, acute angina pectoris, and recent myocardial infarction because of the risk of increased myocardial workload and constriction of coronary arteries. The use of NRT during pregnancy is not approved by the FDA because of possible risk to the fetus; however, some experts recommend NRT use during this period because of the even higher risks of continued smoking. When used during pregnancy, lower and intermittent dosing methods should be used, such as nicotine gum, nasal spray, or inhaler.
Nicotine polacrilex gum, which is available without a prescription, provides nicotine that is absorbed through the buccal mucosa. The gum also decreases smoking craving by offering oral stimulation and helping relieve boredom, and it diminishes the patient's fear of weight gain after smoking cessation. This gum is best used on a fixed schedule rather than as-needed to control cravings. Because of its high viscosity, nicotine gum may not be appropriate in patients with temporomandibular joint diseases, dentures, bridges, or other significant dental work. The transdermal nicotine patch delivers a constant low level of nicotine across the skin. Daily dosing can be tailored by varying the patch strength and length of delivery (16 or 24 hours). Reactions to the adhesive are common and can be relieved by using a 1 percent hydrocortisone cream, oral antihistamines, or a change in the brand of patch. Compliance is generally high with this once-daily dosing system.
Nicotine nasal spray is rapidly absorbed across the nasal mucosa. Some patients may initially develop nose and throat irritation, watery eyes, sneezing, or coughing, but tolerance usually develops rapidly. Because of its rapid onset of action, the spray is useful in patients who need to treat withdrawal symptoms quickly. The nicotine inhaler system uses a cartridge and mouthpiece that offer vaporized nicotine that is absorbed across the oropharyngeal mucosa. Deep inhalation is not appropriate because this will increase nicotine delivery, resulting in more adverse effects. Local irritation is common early in the course of use, but tolerance develops rapidly.
Sustained-release bupropion appears to support smoking cessation by blocking do-pamine and norepinephrine reuptake, reducing nicotine cravings and withdrawal symptoms. Because of the need to build up a therapeutic level, bupropion should be started one to two weeks before smoking cessation begins, with the initial dosage being 150 mg per day for two days, then increasing to 300 mg per day. The most common adverse effects include insomnia and dry mouth, but both usually resolve with continued use. The increased seizure risk with bupropion means this medication is contraindicated in patients with a high risk of seizures. Bupropion can be used in combination with NRT.
Although they are not approved by the FDA for smoking cessation, other medications are used as second-line treatments for smoking cessation, including clonidine and nortriptyline. Effective dosages of clonidine range from 0.15 to 0.75 mg orally (or 0.1 to 0.2 mg transdermally) daily for three to 10 weeks. Dosages for nortriptyline are 25 mg at bedtime, increasing up to 75 to 100 mg daily for up to 12 weeks. The utility of combination NRT or high-dose NRT has not been established, but it may help some refractory patients who have been unable to quit using single-agent therapy or conventional-dose therapy.
The authors conclude that all patients who attempt to stop smoking should be given a first-line medication to increase their chances of success, unless the medication is contraindicated. Choice of treatment depends on individual factors, including patient preference, medication compliance issues, specific contraindications, history of depression, and level of smoking. Appropriate instructions should be provided with all forms of pharmacotherapy. Behavior counseling provided with treatment increases long-term cessation rates.
editor's note: The Cochrane Collaboration has reviewed several aspects of smoking cessation. Physician advice about smoking cessation appears to provide a small but significant increase in the chance that a patient will quit. It is less clear whether intensive counseling is more effective than brief counseling or whether follow-up increases the likelihood of cessation. Intensive interventions appear to increase effectiveness marginally. NRT is a useful part of a smoking cessation strategy and increases quit rates up to two times, regardless of the setting. The 4-mg gum was shown to be significantly more effective than the 2-mg gum. Combinations of NRT were shown to be possibly more effective than a single treatment. The effectiveness of NRT appears to be independent of other support efforts. Bupropion and nortriptyline can increase smoking cessation rates, and there is some evidence that the combination of bupropion and nicotine patches has a higher quit rate than patches alone. Clonidine appears to be a successful cessation aid, but its use is limited by side effects, including dry mouth and sedation. The role of anxiolytics in smoking cessation is unclear. We can only conclude that smoking cessation is a difficult process for our patients, but we can help them with appropriate use of supportive drug therapy and, perhaps, intensive follow-up, encouragement, and other supportive measures.—r.s.