Disturbed Intrarenal Distribution of Gentamicin in Experimental Pyelonephritis Due to Escherichia coli

Abstract

The intracortical, medullary, and papillary distribution of gentamicin was studied in normal and pyelonephritic rats. The animals were evaluated from 1 hr to 365 days after the end of therapy with either a single dose or two daily injections given every 12 hr for seven days. The serum levels of gentamicin at 1 hr were significantly (P < 0.001) higher in the pyelonephritic rats than in the normal animals after one dose (26 vs. 12 µg/ml) and 14 doses (25.7 vs. 8.8 µg/ml). Peak concentrations of gentamicin in all parts of infected kidneys were significantly (P < 0.001) higher than in normal kidneys. Gentamicin was still detectable at levels of 1.2 µg/g in the cortex of one pyelonephritic animal one year after the end of therapy, when the levels of both serum creatinine (1.1 mg/100 ml) and blood urea nitrogen (30 mg/100 ml) were much higher than at seven days after the end of therapy (0.5 and 19 mg/100 ml, respectively).