Norfloxicin

The quinolones are antimicrobial agents that inhibit the activity of DNA gyrase and topoisomerase IV. The fluoroquinolones are divided into 2 groups, based on antimicrobial spectrum and pharmacology: The quinolones are active against a broad range of bacteria including Enterobacteriaceae, Streptococci, Chlamydia and Legionella. Older quinolones such as ciprofloxacin and norfloxacin have poor activity against streptococci and anaerobes. The quinolones are widely distributed to most body fluids and tissues. They are variably metabolised in the liver and excreted in the urine. Quinolones are used extensively in veterinary medicine and their use in food producing animals could result in potentially harmful concentrations in tissue, organs and milk. The potential risk is reduced by withdrawal of the drug for a fixed period before slaughter, although residual levels may remain.