Oxprenolol

The Cochrane Database of Systematic Reviews (CDSR). The CDSR is an ever-growing collection of highly structured systematic reviews of randomized controlled trials. Contributors to the CDSR make a concerted effort to find every randomized trial (published or unpublished) addressing their question of interest and use explicit validity criteria to determine which trials to include in their review. Meta-analysis is often used to combine results, but data from individual trials are presented as well, along with a brief description of the methods of each trial. Contributors agree to produce annual updates of each of their reviews, incorporating new trials as they become available. The CDSR is published quarterly in electronic format and distributed as a part of "The Cochrane Library" on disk, CD-ROM, or via the Internet. Additional information about the Cochrane Library and how to access it is available on the Internet at http://www.cochrane.co.uk/

Clinical question What are the most effective methods to help patients quit smoking?

Background Physicians often become discouraged when trying to motivate their patients who smoke to quit. Even a few successes can have huge benefits, however, since smoking is a major risk factor for much morbidity and mortality. Six Cochrane reviews now address the effectiveness of different smoking cessation interventions.

Results Physician Advice for Smoking Cessation. (Silagy C, Ketteridge S. Date of most recent substantive amendment: July 29, 1997.) The authors identified 29 randomized trials (with a total of more than 27,000 participants) in which patients who were provided with advice from their physician to quit smoking were compared with a control group who did not receive such advice. In some trials, patients were given a minimal additional intervention, such as a brief pamphlet or a single follow-up visit. In other trials, patients received more intensive interventions. Success was defined as continued cessation for a period of 6 months or longer. Of the studies included, 38% used some biochemical method to validate smoking cessation. Most of the studies were done in family or general practices; the remainder in outpatient clinics or occupational settings.

Brief, simple advice by physicians was clearly successful. Even minimal interventions produced cessation rates 2.3% higher than the control group rates. More intensive interventions (such as those which allowed more than 20 minutes per visit, provided more than one follow-up visit, or used more extensive handouts) had more impressive results, with a 5.8% increase in smoking cessation rates. The addition of other interventions, such as pulmonary function testing or feedback of carbon monoxide levels, did not improve cessation rates. Advice was slightly more effective for patients at high risk of developing a smoking-related illness.

Nicotine Replacement Therapy for Smoking Cessation. (Silagy C, Mant D, Fowler G, Lancaster T. Date of most recent substantive amendment: May 13, 1997.) A comprehensive search for trials in which patients were randomized to receive nicotine replacement therapy (NRT) or a matching placebo found 47 studies evaluating nicotine gum, 22 trials evaluating nicotine patches, 3 using nicotine in a nasal spray, and 2 using an inhaler. A total of 27,300 patients were involved in the studies and 16 of these trials were performed in primary care settings.

All forms of NRT were better than placebo at helping smokers remain abstinent for 6 months or longer. There were no significant differences in the effectiveness of the various NRT delivery systems. The 4-mg nicotine gum was more than twice as effective as the 2-mg formulation among highly addicted smokers. There was a nonsignificant trend toward greater effectiveness of the 16-hour patches, when compared with 24-hour patches. Continued use of the patch beyond 8 weeks did not improve cessation rates. High-strength patches (44 mg) or combinations of patch and gum were no more effective than regular strength patches used alone. In all of the trials, smokers received at least some form of brief advice.

Anxiolytics and Antidepressants in Smoking Cessation. (Hughes JR, Stead LF, Lancaster TR. Date of most recent substantive amendment: June 2, 1997.) Anxiety and depression are frequent symptoms during nicotine withdrawal. The use of mood-altering drugs has therefore seemed to be a potentially useful way to help smokers quit. Unlike NRT, anxiolytics or antidepressants can be used before cessation and might help smokers with the process of quitting. Bupropion has recently been approved by the FDA for this indication.

The authors identified three studies using buspirone, three using bupropion, and one each for meprobamate, diazepam, metoprolol,' oxprenolol, fluoxetine, moclobemide, and nortriptyline. There was no evidence that the anxiolytics or beta-blockers were effective in smoking cessation. The antidepressant studies, however, all showed a statistically significant effect. Studies assessing bupropion and fluoxetine were available only in abstract form and thus it is unclear whether the patients involved were similar to those seen in family practice settings. All of the studies had rather small sample sizes, especially when compared with the thousands of individuals in the studies of advice or NRT. None of the studies assessed the efficacy of antidepressants and NRT used in combination.

Clonidine for Smoking Cessation. (Gourlay SG, Stead LF, Benowitz NL. Date of most recent substantive amendment: November 29, 1996.) Clonidine has been used in the management of withdrawal from opiates or alcohol, and has recently been found to ease smokers' withdrawal symptoms. In five randomized trials (with 722 participants) clonidine given by mouth or via a patch had a similar efficacy to that reported for NRT. The high rates of adverse effects (dry mouth, sedation, dizziness, postural hypotension) led many patients taking clonidine to withdraw from these studies.

Lobeline for Smoking Cessation. (Stead LF, Hughes JR. Date of most recent substantive amendment: May 27, 1997.); Acupuncture in Smoking Cessation. (White AR, Rampes H. Date of most recent substantive amendment: November 24, 1996.); Silver Acetate for Smoking Cessation. (Lancaster T, Stead L. Date of most recent substantive amendment: June 20, 1997.) Some interventions appear to be ineffective. Sixteen randomized trials showed no difference in smoking cessation rates for patients randomized to acupuncture, sham acupuncture, or no treatment. Silver acetate, available in gum or lozenges, produces an unpleasant metallic taste in combination with cigarettes and leads to no improvement in smoking cessation rates. Lobeline, an alkaloid derived from the leaves of an Indian tobacco plant, is considered a partial nicotine antagonist. There are no data from good studies to support its use in smoking cessation.

Recommendations for clinical practice Brief advice by physicians is effective in helping patients to quit smoking. More intensive interventions are even more effective, but are usually impractical in the context of a busy office practice. Fortunately, the addition of NRT to brief advice results in smoking cessation rates that equal those available from intensive interventions. The various forms of NRT appear to work equally well, thus leaving the clinician some scope to match prescription with individual patients' preferences. With advice and NRT as the first-line approach, antidepressant therapy can also be effective and can be used for patients who are having difficulty quitting completely or who have been unsuccessful in the past with NRT.

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