Basic and clinical studies of loracarbef

We performed basic and clinical studies of loracarbef (LCBF), a new carbacephem, with the following results. 1) Antimicrobial activity The MICs of LCBF against various clinical isolates were determined with an inoculum size of 10⁶ cells/ml. The MIC₈₀ was 6.25 μg/ml for methicillin-sensitive Staphylococcus aureus, 1.56 for Escherichia coli, 25 for Klebsiella pneumoniae, and >100 for methicillin-resistant S. aureus, Enterococcus faecalis, Enterobacter spp., Proteus spp., Citrobacter freundii and Pseudomonas aeruginosa. Its activity was almost equal to cephalexin and cefaclor, but it was much less than that of cefpodoxime against gramnegative bacilli. 2) Serum concentration and urinary excretion Serum concentrations of LCBF were measured in 5 elderly patients without abnormal renal function, given 200 mg of LCBF orally in a fasting condition. The peak mean serum concentration was 8.85 μg/ml one hour after administration. T_1/2 was 1.75 h and AUC was 25.2 μg ⋅ h/ml. The mean 8 h cumulative urinary excretion rate was 84.8%. 3) Clinical efficacy and adverse reactions One patient with pneumonia, 1 with acute bronchitis, 2 with acute tonsillitis, 1 with acute pharyngitis, and 1 with furuncle were treated with LCBF at a daily dose of 600 ~ 1200 mg for 4 ~ 21 days. Clinical response was excellent in one patient and good in 5. Causative organisms were eradicated in 3 patients and decreased in one patient with acute tonsillitis caused by S. aureus and Streptococcus milleri. Adverse reactions and abnormal laboratory findings were not observed.