Cephalexin: absorption and excretion as related to renal function and hemodialysis.

Cephalexin is a new semisynthetic cephalosporin C derivative, which is well absorbed from the gastrointestinal tract and excreted in high concentration in the urine. Even in patients with impaired renal function, the concentrations of cephalexin present in the urine are adequate for the treatment of most urinary tract infections produced by Escherichia coli, Klebsiella, and Proteus mirabilis. In anephric patients, single doses of 250 or 500 mg of cephalexin resulted in high, prolonged serum concentrations. Peak levels were usually observed within 1 hr. However, in two of six anephric patients, peak levels were reached after 6 and 12 hr due to delayed absorption. Hemodialysis for 6 hr reduced the serum concentration of cephalexin by 58%.