PubMed1988
Furosemide (0.5 mg/kg, i.v.) was administered to 31 healthy, day-active adults (Group 1) at 07:00 h (study 1) and urine output during the next 2 h was collected. Urine volume, urinary sodium, potassium and creatinine were determined. After 60 h, furosemide (0.5 mg/kg, i.v.) was administered at 19:00 h (study 2) and urine output during the subsequent 2 h (19:00 h to 21:00 h) was collected for estimation of urine volume, sodium, potassium and creatinine. Twenty-two healthy, day-active adults (Group 2) who constituted the control group underwent study 1 and study 2 and received 2 ml of normal saline instead of furosemide. There was no significant difference in urinary volume, urinary sodium, potassium and creatinine excretion between study 1 and study 2 in the control subjects (Group 2). In contrast, administration of furosemide at 07:00 h (study 1) resulted in greater diuresis (247.1 +/- 202.07 ml), more marked sodium excretion (42.66 +/- 29.06 mmol), increased potassium excretion (5.14 +/- 4.014 mmol), and greater creatinine excretion (0.415 +/- 0.414 mmol) as compared to study 2. In conclusion, the diuretic, natriuretic and kaluretic effects of furosemide are greater when administered at 07:00 h than at 19:00 h. Therefore, in clinical practice, the time of administration of furosemide can be so chosen as to achieve a greater diuresis or to prevent a marked loss of sodium.