Pharmacokinetics of ofloxacin in severe chronic renal failure

The pharmacokinetics of ofloxacin were studied in patients with severe renal impairment. In five healthy subjects and nine patients with chronic renal failure (CRF) (creatinine clearance CCR] less than 20 ml/min) receiving 100 mg of ofloxacin orally in the fasted state, the serum concentration was measured over the subsequent 48 hours. Intracorporeal dynamics were examined, employing a one-compartment open model. Ofloxacin levels were measured using the paper disk method. The half-life of ofloxacin was markedly prolonged, to 23.1 +/- 7.0 hr in the CRF group versus 2.9 +/- 0.5 hr for healthy subjects. In the CRF group, the maximum concentration and area under the curve were greater than in healthy subjects. There were no significant differences in volume of distribution between the two groups. The renal clearance of ofloxacin decreased from 261.0 +/- 46.6 ml/min in healthy subjects to 8.0 +/- 4.7 ml/min in the CRF group and correlated significantly with CCR in the CRF group (r = .88, P less than 0.01). There were no significant differences in nonrenal clearance between the two groups. The 24-hour renal excretion of ofloxacin averaged 91.9 +/- 5.4% and 14.1 +/- 5.5% of the dose in the healthy and CRF groups, respectively. In three hemodialysis patients on the regular hollow-fiber dialyser, the dialysance of ofloxacin was about 50% that of creatinine. Based on these findings, a reduction in the dose of ofloxacin is necessary in patients with CRF. In the hemodialyzed patients, its high dialyzability should be considered when deciding dose regimens.