The diuretic dilemma and the management of mild hypertension.

Diuretics are used in first-step antihypertensive monotherapy or in combination with adrenergic-inhibiting agents in the majority of hypertensive patients in the United States. A 30-year experience has demonstrated that blood pressure is lowered to as great or greater a degree with diuretics than when many of the presently available antihypertensive drugs, including converting enzyme inhibitors, calcium entry blockers, beta- or alpha-adrenergic inhibitors, or centrally acting sympatholytic agents, are used. Diuretics appear to be especially effective in the elderly and in black patients. All of the major hypertension clinical trials upon which we base our decisions for treatment have employed diuretics as step-1 therapy--with a reduction in morbidity and mortality. In addition, data suggest that more effective treatment of hypertension has contributed to the decrease of over 45% in deaths from cerebrovascular disease and the overall reduction of cardiovascular deaths over the past 15 to 20 years in the United States. The debate concerning the long term safety of diuretic therapy has focused on the USA Multiple Risk Factor Intervention Trial (MRFIT) results and several papers, suggesting that the lipid-raising or potassium-lowering properties of diuretics may produce adverse effects. Suggestions have been made that the use of other drugs without metabolic side effects may result in greater benefit with less risk, especially in the management of mild hypertension where the risk of the disease is not immediate or great. A review of the MRFIT and lipid data from long term studies has failed to establish the 'toxicity' of diuretic agents. In addition, recent studies have not confirmed previous observations that diuretic-induced hypokalaemia increases ventricular ectopy or contributes to sudden death. Although hypokalaemia should be avoided and corrected if it occurs, especially in patients with ischaemic heart disease, in the elderly, in patients with pretreatment ectopy or in patients on low potassium diets, the fear of this metabolic side effect of diuretics should not deter the physician from continuing the use of these agents both as monotherapy in most patients and as second-step therapy with an adrenergic-inhibiting drug.