Fluoroquinolones. Adverse reactions during clinical trials and postmarketing surveillance.

The knowledge of side effects of fluoroquinolones during clinical trials and postmarketing surveillance is reviewed. Gastro-intestinal side effects (observed in 3-6% of the patients) are the most frequently observed side effects followed by side effects of the central nervous system (0.5-1.5%) and skin reactions (0.5-2%). The incidence of severe side effects is very low and most effects can be reserved rapidly upon discontinuation of therapy. Reactions of the central nervous system (sometimes severe) were the most often spontaneously reported events during the postmarketing surveillance of ofloxacin. The incidence of adverse reactions is usually in the same range as that of other antimicrobial agents like the third generation cephalosporins, imipenem and aztreonam. Fluoroquinolones are usually well-tolerated and safe drugs, but more data is needed on the long-term safety of quinolones, the safety in children, in elderly people and in severely ill patients.