Objective: To evaluate the effect of peritoneal lavage on pharmacokinetics of gentamicin sulfate in healthy horses after experimental celiotomy.
Animals: 13 clinically normal horses.
Procedure: Horses were randomly assigned to control or experimental groups. All horses received gentamicin (6.6 mg/kg of body weight, IV, q 24 h) before surgery, underwent experimental abdominal surgery, and had abdominal drains placed percutaneously. Horses of the experimental group received postoperative peritoneal lavage; horses of the control group did not receive peritoneal lavage. The day after surgery, 24 hours after the preoperative dose of gentamicin, a second dose of gentamicin was administered. Three and 15 hours after this second dose of gentamicin, horses of the experimental group received peritoneal lavage. Venous blood was obtained, for determination of concentration of gentamicin, immediately before and at specified intervals during the 24-hour period after the second dose of gentamicin.
Results: There were no differences in any of the pharmacokinetic values of gentamicin between horses of the control and experimental groups.
Conclusions: Peritoneal lavage had no effect on pharmacokinetics of gentamicin in healthy horses after abdominal surgery, in which localized nonseptic peritonitis was induced.
Clinical relevance: Peritoneal lavage in horses with localized nonseptic peritonitis or for the prevention of intra-abdominal adhesions should not necessitate alteration of the dosage of gentamicin to maintain predictable serum concentrations.