An experimental evaluation of the pharmacokinetics of fusidic acid in peritoneal dialysis.

Fusidic acid, an antimicrobial agent with activity against coagulase-positive and coagulase-negative staphylococci, has considerable potential for the management of staphylococcal peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). Whether fusidic acid reaches therapeutic levels in the dialysate once therapeutic serum levels have been achieved is not known. An animal model of CAPD that reproduced essential features of the clinical procedure was used to investigate this issue. Although oral administration was the preferred route, fusidic acid is not absorbed from the gastrointestinal tract of laboratory rats, and a subcutaneous injection of diethanolamine fusidate was used to achieve serum levels of the agent equivalent to those achieved clinically in man. In this model, fusidic acid concentrations up to 28 times the MIC for staphylococci were found in the dialysate when therapeutic levels of the agent were reached in the serum. The data provide support for continued experimental and clinical evaluation of the role of fusidic acid in CAPD-associated peritonitis.