Daily single-dose gentamicin therapy in experimental pyelonephritis.

The therapeutic efficacy of gentamicin given once or three times a day was compared in a model of experimental renal infection in rats. The same amount of gentamicin given either in a single injection or three injections a day produced no statistically significant difference in the treatment of incipient infection. The effect of this mode of administration on advanced infection depended on the length of the therapy. After five days, administration of the same dose given in a single injection or three injections did not result in significant differences. After ten days the therapy proved more effective when gentamicin was injected three times a day. In comparison a single daily dose, amounting to two thirds of the total dose when given three times a day every eight hours, revealed after five days of therapy a statistically significantly lower bacterial count in the kidney than three daily injections of gentamicin.