Effect of Metoclopramide, a Dopaminergic Inhibitor, on Renin and Aldosterone in Idiopathic Edema: Possible Therapeutic Approach with Levodopa and Carbidopa

Abstract

Metoclopramide, a dopaminergic inhibitor, was injected (10 mg iv) in 15 normal women and in 9 patients with clinical evidence of idiopathic edema, while on a 130 meq sodium and 50-70 meq potassium diet. The subjects kept a recumbent position during the test. PRA slightly increased at 45 min (p < 0.01) in normal women, A low sodium diet (20–40 meq/day) seemed to accelerate the PRA response, which was significant at 20 min (P < 0.05). In patients with idiopathic edema, PRA consistently increased at 20, 30, and 45 min (P < 0.05). Plasma aldosterone (PA) increased significantly at 10, 20, 30, 45, and 60 min (P < 0.005) both in normal women and in patients. The absolute change of PA from 0–10 min was significantly higher in patients with idiopathic edema (P < 0.001) and preceded the increase of PRA. In 5 normal women, urinary sodium decreased and urinary potassium increased after metoclopramide. Serum electrolytes were not modified. In 2 patients with idiopathic edema and hypokalemia, the treatment with a central dopaminergic agonist (250 mg levodopa and 100 mg carbidopa) reduced PRA and PA, restored serum potassium to normal values, and increased urinary excretion of sodium. These data suggest a dopaminergic control of renin and aldosterone and an alteration of this control in idiopathic edema.