Renal clearance of imipenem in children.

Imipenem renal clearance was studied in six children (three males, three females; 2.9-11.2 years of age) following a single intravenous dose (21.7 +/- 5.1 mg/kg) of imipenem/cilastatin (1:1). In an approximately six-hour period following drug administration, 65.3 +/- 9.7% of the imipenem dose was excreted in the urine unchanged. The renal clearance (280.03 +/- 24.34 ml/min/1.73 m2) of imipenem was found to account for 69.2% of the corresponding plasma imipenem clearance (404.89 +/- 24.83 ml/min/1.73 m2). Contrary to existing adult data, the imipenem renal clearance in our subjects was 1.95-fold greater than the estimated creatinine clearance, suggesting significant tubular secretion of imipenem in children. Examination of urinary imipenem excretion rate versus plasma concentration relationships in three of the children revealed a potential renal tubular reabsorption component for imipenem in children. Comparison of renal imipenem clearance data in these children to similar data from adults suggests that quantitatively important developmental differences may exist for the renal handling of imipenem.