Choosing the right beta-blocker. A guide to selection.

beta-Blockers have been in clinical use for 30 years, and have an accepted role in (among others) the treatment of high blood pressure, the secondary prevention of myocardial infarction and the treatment of arrhythmias. Their place in the treatment of heart failure is currently under investigation. The drugs available in the 1970s and early 1980s were subjected to intense investigation. A new generation of beta-blockers, including some such as carvedilol and bucindolol, with vasodilating properties, is now appearing. As yet these later agents have not been the subject of large clinical trials. Clinical practice involves the treatment of individual patients with defined dosages of particular drugs. It is, therefore, not acceptable to base practice on theories derived from the clinical pharmacology of a particular drug, on the results of small trials or on a meta-analysis of results from a number of trials that were individually inadequate. Clinical practice must follow the results of large-scale trials in defined populations. The major trials in hypertension, myocardial infarction, arrhythmias and heart failure provide the best evidence for the use of individual beta-blockers in each of these clinical situations. In patients with high blood pressure, beta-blockers do not seem to have any particular advantage over other hypotensive agents. In myocardial infarction, relatively late use of a beta-blocker undoubtedly reduces fatality, though the value of early treatment is less clear. beta-Blockers are not powerful antiarrhythmics, but they do appear to prevent sudden death. Their possible role in heart failure is perhaps the most interesting current field of beta-blocker research. There are very few comparative studies of beta-blockers, and it is difficult to make precise recommendations. None of the new generation of beta-blockers has yet been used in a trial that is large enough trial for any of them to be accepted for routine use in preference to older drugs. The use of individual beta-blockers, as with any drug, should follow the results of clinical trials. Propranolol and atenolol have been studied most intensely in hypertension. For secondary prevention of myocardial infarction, the evidence is best for timolol. Sotalol is probably the best antiarrhythmic among the beta-blockers. Whether any individual beta-blocker is best for heart failure remains to be seen.