THE ALDOSTERONE BLOCKING EFFECTS OF SPIROLACTONES

Abstract

The spirolactones are drugs which exert an aldosterone-blocking effect Aldosterone plays a significant role in the development of edema in certain disease states and the administration of spironolactone (Aldactone) to such patients will produce a diuresis. Because of its aldosterone-blocking effects Aldactone is of particular value in the patient who has become refractory to continued treatment with the thiazides or mercurials. In contrast to the thiazides and mercurials, Aldactone appears to retain its effect in promoting Na excretion for many months or even years when used alone or in combination with other diuretics. The acute diuretic potency of Aldactone is not comparable to that of the thiazides or mercurial diuretics. However, as Morrison has pointed out there is something to be gained from a drug that will produce a slow but progressive diuresis over a period of several weeks than from an agent that acts more rapidly but loses its effectiveness when used daily. Secondly, Aldactone neither increases urinary K increase nor decreases serum concentration as most other diuretics do. In fact, Aldactone will reverse the tendency of the thiazide drugs to produce K depletion. Lastly, since aldosterone acts in the distal renal tubules to cause Na retention and K excretion, Aldactone also exerts its blocking effect at the distal tubules. Such is in contrast to the mercurials and thiazides which produce their effect in the proximal tubules of the kidney. Thus, because of the different sites of action of these compounds Aldactone in combination with the other diuretics can produce a true synergistic diuretic effect, which is very valuable in the patient with resistant edema.