 As with all drugs within this class, flumequine therapy may result in severe central nervous system (CNS) reactions, phototoxicity resulting in skin reactions like erythema, pruritus, urticaria and severe rashes, gastrointestinal and neurological disorders.Flumequine was found to have no effect on theophylline pharmacokinetics.Flumequine is a 9-fluoro-6,7-dihydro-5-methyl-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid.