Pharmacokinetics of enoxacin and its oxometabolite following intravenous administration to patients with different degrees of renal impairment.
 Enoxacin is a fluorinated quinolone with potential clinical use in the treatment of serious infections.
 Twenty-three patients (age, 19 to 87 years) with different degrees of renal function, including a group undergoing chronic hemodialysis, received enoxacin (400 mg) by intravenous infusion (1 h).
 Blood samples were collected before infusion; at the end of infusion; and at 5, 10, 20, 30, 45, 60, 90, and 120 min and 3, 4, 6, 12, 18, 24, 48, and 72 h after infusion.
 Enoxacin and oxoenoxacin concentrations were measured by high-pressure liquid chromatography.
 Pharmacokinetic parameters (mean +/- standard deviation) were calculated by using a noncompartmental PK model according to creatinine clearances (in milliliters per minute).
 Total clearance of enoxacin decreased from 4.95 +/- 1.16 ml/min per kg in the group with normal creatinine clearance to 0.76 +/- 0.21 ml/min per kg in the patients with severe renal failure (creatinine clearance, less than 15 ml/min), whereas the elimination half-life increased from 4.5 +/- 1.0 to 20 +/- 5 h, respectively.
 The elimination of oxoenoxacin (the main metabolite of enoxacin) in urine was markedly decreased when creatinine clearance was less than 15 ml/min.
 Hemodialysis removed an insignificant amount of enoxacin and oxoenoxacin.
 These data indicate that as creatinine clearance falls below 30 ml/min, the daily enoxacin dose should be reduced by half.
 During prolonged administration of enoxacin to patients with creatinine clearances of less than 30 ml/min, the accumulation of oxoenoxacin might lead to unexpected side effects.
