Diuretic effect of slow-release furosemide in elderly patients.

To compare the natriuretic and diuretic effects of a slow-release and a standard formulation of furosemide, 18 elderly patients with stable congestive heart failure were hospitalized and treated with one of these formulations in a double blind randomized trial. Patients received placebo on the first 2 days, furosemide on the third day and placebo again on the last 2 days of the study. In patients receiving the standard formulation mean urine output was increased only on the day of active treatment. However, in patients who had received the slow-release preparation, increased urine excretion was seen both on the day of active treatment and on the subsequent day. The total diuresis (0-48 h) in the 2 groups was equal, but a peak diuresis (0-6 h) was seen only in patients on the standard formulation of furosemide. Sodium excretion followed the pattern of urine excretion. Furosemide in a slow-release formulation offers advantages in maintenance therapy in congestive heart failure, especially in elderly patients.