Low Dose Loop Diuretics in Essential Hypertension. Experience with Torasemide

Diuretics belong to the class of antihypertensive drugs recommended for first-line therapy of essential hypertension. Although they are widely and effectively used for the treatment of hypertension, the question remains whether their possible negative influence on metabolic and electrolyte parameters could partly offset the benefit of blood pressure reduction with respect to reduction of coronary artery disease. Recently published data demonstrate that much lower doses of thiazides exert the same antihypertensive effect as the higher doses used in the past and even prescribed today. These lower doses produce relatively little change in biochemical parameters. Thus, the postulated risks can be avoided by using the lowest effective dose. Traditionally, loop diuretics of the furosemide (frusemide) type are rarely used as first-line antihypertensive agents. They seem to display less efficacy coupled with an intense diuresis when used in standard available doses. However, there is evidence that newly developed loop diuretics, in lower doses than used in congestive heart failure, are effective antihypertensive agents. For example, torasemide 2.5mg once daily, which does not exert a significant diuresis over 24 hours compared with placebo, lowers elevated blood pressure to a similar extent than thiazides or related compounds. This antihypertensive effect is accompanied by less, if any, changes in metabolic or electrolyte parameters compared with widely used standard diuretics such as hydrochlorothiazide, indapamide or chlorthalidone. The influence on serum potassium and magnesium is similar to or even less than fixed combinations of hydrochlorothiazide and triamterene or amiloride. Thus, low-dose torasemide constitutes an alternative to established thiazide antihypertensive therapy.