The penetration of amoxycillin/clavulanic acid into peritoneal fluid.

Thirty patients undergoing elective abdominal surgery were given 1 g amoxycillin plus 0 . 2 g clavulanic acid as a single intravenous injection at varying times prior to the operation. Sterile assay discs were placed on the peritoneal surface in order to measure peritoneal fluid levels of each agent. Simultaneous serum levels were also measured. A total of 44 simultaneous serum and peritoneal samples were analysed. There was rapid penetration of both agents into peritoneal fluid. The mean peritoneal fluid levels of amoxycillin were 84% (S.D. 34) of the serum level and 66% 42) for clavulanic acid. The peritoneal levels of both agents declined in parallel to the serum levels (the half-lives all being about 1 h) and the ratio of amoxycillin: clavulanic acid in serum and peritoneal fluid was similar to that as administered.