Chronopharmacological study of furosemide in human subjects.

The present study was undertaken to determine whether the effects of furosemidedepend on the administration time or not. After furosemide 20 mg or distilled water wasadministrated intravenously in 12 human volunteers at 9: 00 or at 21: 00, urine volumeand urinary excretion of sodium, choride, and furosemide were measured. There was nosignificant difference in urine volume and urinary excretion of sodium and chloridebetween when distilled water was given at 9: 00 and when given at 21: 00. Whenfurosemide was administrated at 21: 00, urine volume and urinary excretion of sodium, chloride, and furosemide during 60 min were significantly greater those administrated at9: 00. There was a marked correlation between the urinary output of furosemide and theurine volume, urinary sodium or chloride. These results suggest that the effects offurosemide vary with the administration time and the observed variations are mainlydependent on the amount of furosemide secreted to urine.