The JNC 7 guidelines recommend thiazide diuretics as first line treatment in uncomplicated hypertension. The rationale for this recommendation comes from the results of the ALLHAT trial, where thiazide diuretic was equally effective as calcium channel blocker and angiotensin converting enzyme inhibitor in the prevention of serious cardiovascular events and even more effective than the other drugs in the reduction of some cardiovascular complications (stroke, heart failure).
This review presents arguments for and against this opinion. Mechanisms of antihypertensive action of thiazide diuretics, their metabolic and electrolyte adverse reactions, end-organ protection and the results of other clinical trials are discussed and compared with placebo and other, newer antihypertensives. The authors also review the indications for thiazide diuretics in hypotensive treatment. It seems that in the light of the recent clinical trials thiazide diuretics should be used more widely but there is little evidence that they should be regarded as first line treatment in every case of hypertension.