Cephalexin: human studies of absorption and excretion of a new cephalosporin antibiotic.

1. Serum levels, half-lives and urine concentrations of cephalexin, an oral cephalosporin antibiotic which is unique in its absorption and excretion, are reported in human volunteers, fasting, non-fasting and non-fasting plus probenecid. Accumulation does not seem to occur.2. Cephalexin clearance was 376 ml./min and the ratio of cephalexin/creatinine clearances was 2.6 in one volunteer.3. Cephalexin had no effect on the urinary excretion of leucocytes, red cells or protein.4. The very high rate of absorption giving high serum levels and urine concentrations suggest cephalexin will be a useful antibiotic in susceptible bacterial infections in man.