New classification and update on the quinolone antibiotics

The newer fluoroquinolones have broad-spectrum bactericidal activity, excel lent oral bioavailability. good tissue penetration and favorable safety and tolerability profiles. A new four-generation classification of the quinolo ne drugs takes into account the expanded antimicrobial spectrum of the more recently introduced fluoroquinolones and their clinical indications. First -generation drugs (e.g.. nalidixic acid) achieve minimal serum levels. Seco nd-generation quinolones (e.g.. ciprofloxacin) have increased gram-negative and systemic activity. Third-generation drugs (e.g.. levofloxacin) have ex panded activity against gram-positive bacteria and atypical pathogens. Four th-generation quinolone drugs (currently only trovafloxacin) add significan t activity against anaerobes. The quinolones can be differentiated within c lasses based on their pharmacokinetic properties. The new classification ca n help family physicians prescribe these drugs appropriately.