Pharmacokinetics of piperacillin and gentamicin following intravenous administration to dogs.

Piperacillin sodium was administered intravenously to dogs, alone or in combination with gentamicin, twice a day (approximately 5 hr apart) for 36-37 days. The pharmacokinetics of neither drug changed in the presence of the other; however, the percentage of the gentamicin dose recovered in the urine decreased significantly when coadministered with piperacillin. The data demonstrate that interaction between the two drugs in urine is feasible.