The use of beta blockers following myocardial infarction--doubts.

Several good clinical trials have shown that long-term treatment with beta-adrenoceptor blocking drugs reduces the fatality rate of patients who have had a myocardial infarction. Nevertheless such treatment has not become routine clinical practice for many physicians because doubts about these compounds persist. It is not clear how beta blockers reduce fatality, nor whether any one of this group of drugs is more effective than any other. Beta blockers produce adverse reactions and the risks of treatment have to be balanced against the benefits. It is not clear when treatment should begin, nor when it should stop. It is not possible to identify a sub-group of patients who should be given a beta blocker and another group in which treatment is unnecessary. Finally, any change in routine clinical practice for post-infarction patients might make future trials of other different types of drug difficult to conduct.