A preliminary report on the pharmacokinetics of ofloxacin, desmethyl ofloxacin and ofloxacin N-oxide in patients with chronic renal failure.

The in vitro activities of ofloxacin, desmethyl ofloxacin and ofloxacin N-oxide were determined and a specific high performance liquid chromatography (HPLC) assay for these 3 compounds was devised as part of a study of the pharmacokinetics of ofloxacin and its metabolites in patients with impaired renal function. Desmethyl ofloxacin had significant antimicrobial activity but less than that of the parent drug. In 2 patients with chronic renal failure, specific HPLC assay indicated an extended half-life for ofloxacin (approximately 13 hours) and the appearance in serum of low concentrations of both metabolites after 10 hours, persisting until the last blood sample was taken (32 hours). Further studies using specific assays are needed, particularly in patients undergoing haemodialysis and after administration of multiple doses.