Importance of Time of Furosemide Administration on the Diuretic, Natriuretic, and Kaliuretic Effects

Abstract

Circadian rhythms can alter the rate at which drugs are absorbed, distributed, metabolized, and/or excreted. Thus, a fixed dose of drug may result in varying responses depending on the time of administration. The present study investigates the chrono-pharmacology of furosemide, a ‘loop’ diuretic used in urologic practice. Furosemide (0.5 mg/kg, i.v.) was administered to 31 healthy adults (Group I) at 0700 h and urine was collected for the next 2 h (Study I). After 60 h, the same dose of furosemide was administered at 1900 h and urine was collected again for the subsequent 2 h (Study II). Twenty-two control subjects (Group II) also underwent Studies I and II but received 2 ml of normal saline instead of furosemide. The 2-h urine output and Na, K, and creatinine excretions were determined (Table 1).