9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid levofloxacin An optically active form of ofloxacin having (<i>S</i>)-configuration; an inhibitor of bacterial topoisomerase IV and DNA gyrase. CHEBI:6440 Lfx quinolone antibiotic fluoroquinolone antibiotic second line or reserve tuberculosis drug