TIME-DEPENDENT CHANGE IN THE TOXIC EFFECTS OF AMIKACIN ON RENAL FUNCTIONS

The present study was undertaken to examine whether there was a time-d ependent change in the toxic effects of amikacin, an aminoglycoside, o n renal functions. Male Wistar rats were maintained under conditions o f light from 7 am to 7 pm and dark from 7 pm to 7 am. Amikacin (1.2 g/ kg) was injected intraperitoneally to animals at 4 am, 10 am, 4 pm or 10 pm. Glomerular function estimated by creatinine clearance (Clcr) an d tubular function estimated by urinary excretion of a loop diuretic, furosemide, which was excreted in urine mainly by tubular secretion, w ere determined before and 24 hours after amikacin injection. The value s of these parameters were reduced by amikacin at each observation poi nt. The magnitude of these decrements was greatest at 4 pm both for Cl cr and urinary furosemide excretion. These results suggest that the to xic effects of amikacin on renal glomerular and tubular functions vary with its time of administration.