Effects of loop diuretics on carbohydrate metabolism and electrolyte excretion.

The effects of two loop diuretics, bumetanide and furosemide, on carbohydrate metabolism and electrolyte balance were assessed in 11 normal male subjects in a double-blind manner. Glucose, insulin, glucagon, and growth hormone responses to 5-hour glucose tolerance test and arginine infusion were measured during the control and drug treatment periods. Three other non-insulin-dependent diabetic subjects, receiving diuretic drug for six weeks, underwent a similar protocol. Kaliuresis and natriuresis due to diuretic administration were significant only on day 1 of treatment. There were no significant changes in total body potassium by 40K counting; net potassium loss by balance study was minimal in both the acutely treated subjects and the chronically treated patients. Effects of bumetanide and furosemide on water and electrolyte excretion did not differ. Glucose tolerance was significantly improved with bumetanide but not with furosemide. Plasma insulin, glucagon, and growth hormone levels during the oral glucose tolerance test were unaffected by either drug. Insulin levels with arginine infusion were significantly increased, and growth hormone levels decreased with bumetanide but not with furosemide. No evidence of impaired carbohydrate metabolism in the three chronically treated diabetic subjects was seen. It is concluded that the effects of bumetanide and furosemide on potassium balance and glucose utilization were minimal in this experimental setting.