Quinolone-cation interactions: a review

The quinolone class of antibiotics is enjoying a recent resurgence in interest and use due to the development of improved compounds. Norfloxacin, ciprofloxacin, and, most recently, ofloxacin have been marketed. Enoxacin and other agents are in various stages of investigation. These newer compounds are often used for indications not successfully treated by the original quinolones, or in some cases, not optimally treated with any previously available oral antibiotic. A potential problem with the increasing use of quinolone-type antibiotics for systemic illness is the chelation and inactivation of these compounds by several cations. One outcome of these potential interactions is a possible reduction in bioavailability and effectiveness of quinolone compounds. A review of the literature on quinolone-cation interactions, in vivo and in vitro significance, and recommendations to avoid potential problems are provided.