Levofloxacin (Fluoroquinolone) is a broad-spectrum antibiotictopoisomerase IIandtopoisomerase IVinhibitor, used to treat respiratory, urinary tract, gastrointestinal, and abdominal infections. In vitro
Levofloxacin is active against most aerobic Gram-positive and Gram-negative organisms and demonstrates moderate\xa0activity\xa0against anaerobes. Levofloxacin is two-fold more active than ciprofloxacin against Streptococcus pneumoniae and 2- to 4-fold more active than ciprofloxacin against Staphylococcus aureus, Xanthomonas maltophilia, and Bacteroides fragilis. Levofloxacin is two- to eightfold more\xa0active\xa0than ciprofloxacin against coagulase-negative staphylococci and Acinetobacter spp., although these improvements in potency may not be clinically relevant.\xa0Levofloxacin\xa0inhibits 90% of streptococci when it is used at concentrations of 1 mg/mL to 2 mg/mL. Levofloxacin\xa0exhibits twofold greater\xa0inhibitory\xa0and\xa0bactericidal\xa0activities\xa0than ofloxacin\xa0against\xa0either extracellular or intracellular tubercle bacilli.\xa0 Levofloxacin\xa0has the least\xa0inhibitory\xa0effect on osteoblastic cell growth, with a 50%\xa0inhibitory concentration of approximately 80 mg/mL at 48 and 72 hours. Levofloxacin results in strong inhibition of calcium deposition, as determined on day 14 by alizarin red staining and biochemical analysis. Levofloxacin inhibits glycosaminoglycan synthesis initially and DNA synthesis and mitochondrial function secondarily at actual arthropathic concentrations in cultured rabbit chondrocytes but that these changes are reversible and not enough to kill the cells.
In vivo
Levofloxacin is as efficacious as or more efficacious than that with ciprofloxacin in systemic as well as pyelonephritis infections in mice. Levofloxacin achieves higher concentrations in the serum and tissue of mice than does ciprofloxacin. Cell Data