Concentrations of mecillinam and ampicillin determined in serum and renal tissue: a single-dose pharmacokinetic study in patients undergoing nephrectomy.

A study was carried out to determine serum and renal tissue concentrations of antibiotics after a single intravenous injection of 1.0 g ampicillin plus 0.4 g mecillinam, given up to 4 hours before surgery, in 13 patients with normal or near normal kidney function who were undergoing nephrectomy. Both antibiotics showed higher tissue concentrations than the corresponding serum levels. The mean kidney:serum ratio was 2.4 for ampicillin and 1.4 for mecillinam. Serum half-lives were calculated to be 57 minutes for ampicillin and 52 minutes for mecillinam. Corresponding elimination half-lives in the kidney were 45 minutes and 44 minutes, respectively.