Cephalexin for the oral treatment of CAPD peritonitis

Sixteen episodes of peritonitis in 13 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) were treated with oral cephalexin given at each 6-hourly dialysate exchange. Serial measurements of the antibiotic concentration in serum and dialysate were made in seven cases. Cephalexin levels increased rapidly and by 12 h exceeded 27 mg/l in serum and 20 mg/l in dialysate. Dialysate levels considerably exceeded the minimum bactericidal concentration for organisms considered cephalexin-sensitive and in patients with these the clinical response was usually good. Although dialysate concentrations sometimes reached the minimum inhibitory concentration for organisms considered cephalexin-resistant the clinical response in patients from whom resistant bacteria were cultured was unsatisfactory. Intra-peritoneal antibiotic administration would seem unnecessary in many CAPD patients with peritonitis.