New Uses for New and Old Quinolones and the Challenge of Resistance

More than a decade ago ciprofloxacin, the first quinolone with broad indications, was released for clinical use in the United States. The release of ofloxacin, which also had broad applications, followed not long thereafter. Since that time there has been extensive use of these 2 agents and more limited use of other quinolones, such as norfloxacin, enoxacin, and lomefloxacin, which were limited to treatment of infections of the genitourinary tract. Applications of these quinolones largely employed their potent activities against gram-negative bacteria [1, 2]. This article focuses on information developed in the past 4 years on the 4 most recently released quinolones—levofloxacin, sparfloxacin, grepafloxacin, and trovafloxacin [3–8]—and their spectrum of activity, pharmacokinetics, tolerability, and clinical applications. It also focuses on new applications of the older quinolones. Issues of quinolone resistance related to expanding uses of quinolones will also be discussed.