Pharmacokinetics and safety of single oral doses of lomefloxacin.

The pharmacokinetics of 100 mg, 200 mg, 400 mg, 600 mg, and 800 mg of lomefloxacin, a quinolone antimicrobial, were examined in a single sequential rising dose, placebo-controlled, crossover study. Each of 30 healthy male subjects (6 per group) received placebo and one dose of lomefloxacin, separated by 5 days. Test results (physical examinations, laboratory and hematology panels, vital signs, neurological and ophthalmological examinations, EEG or urinalysis) revealed no clinically significant differences compared to baseline. Mean Cmax values (0.92 micrograms ml-1 to 6.99 micrograms ml-1) increased linearly with dose. Mean tmax averaged 1.13 +/- 0.5 h and mean t1/2, 7.8 +/- 1.0 h over all doses. There was a small influence of dose on the AUC0-48. Mean urinary concentrations during the first 4 h postdosing ranged from 79 to 454 micrograms ml-1. Urine concentrations remained greater than or equal to 15 micrograms ml-1 over 24 h at the lowest dose. Maximum urinary excretion rate, Rmax, ranged from 5.84 mg h-1 to 34.90 mg h-1. Dose normalized Rmax and XU96 (per cent of dose) were unaffected by dose. Mean renal clearance decreased at higher doses. In conclusion, lomefloxacin was well tolerated in doses up to 800 mg. Lomefloxacin is rapidly absorbed with an elimination half-life of approximately 8 h. The data suggest that the drug can be effectively administered once daily.