Comparative efficacy of diuretics: benefit versus risk: results of clinical trials.

Although several large trials have been conducted with the aim of establishing the need for, and the best approach to, the treatment of hypertension, none have specifically addressed the question of the best use of diuretics. Analysing the trials to obtain specific answers about diuretics is therefore difficult, and particularly so because of differences in trial design and in the medications used. Comparisons between active treatment and no therapy have tended to show that active treatment is associated with a significant reduction in the incidence of strokes and a small reduction in myocardial infarction and death. Comparisons of treatment strategies, as opposed to comparisons of particular drugs, are hard to interpret and some conclusions that have been drawn about a harmful effect of diuretics are probably misleading. Trials comparing diuretics and beta-blockers suggest that these types of drug have similar effects on clinical events although the most recently published study suggests that diuretics are more effective than beta-blockers in preventing myocardial infarction. Therefore, it seems that what matters is blood pressure reduction, not the means by which this is achieved. The biochemical effects of diuretics are probably not important, but only one trial has investigated the use of a low dose of diuretics.