Pharmacokinetics of ofloxacin and adequacy of maintenance dose for patients on haemodialysis

Abstract

Seven patients, three females and four males, aged 33-70 years, with end-stage renal disease, on regular haemodialysis were treated for various infections with a loading dose of 200 mg and multiple maintenance doses of 100 mg ofloxacin per 24 h over ten days orally. The pharmacokinetics of ofloxacin were studied at the end of the treatment period before, during and after a haemodialysis session. Concentrations in plasma and dialysate were measured by HPLC. Mean trough concentration (+/- S.D.) of ofloxacin before the last drug intake was 1.6 (+/- 0.6) mg/l. At a Tmax of 1.5 (+/- 1.1) h a peak concentration of 3.1 (+/- 1.0) mg/l was reached. The mean half-lives of ofloxacin (+/- S.D.) which were determined in the dialysis-free interval (T1/2 beta) and during the haemodialysis session (T1/2HD) were 38.5 (+/- 14.1) h and 9.9 (+/- 3.4) h, respectively. Mean dialyser clearance (+/- S.D.) was 59.2 (+/- 15.4) ml/min and the fractional removal of ofloxacin amounted to 21.5 (+/- 8.2)%. The data show that in patients with regular haemodialysis treatment a loading dose of 200 mg orally and daily administration of 100 mg orally of ofloxacin results in therapeutically favourable and well tolerated plasma concentrations when given at the end of haemodialysis.