Postmarketing surveillance of quinolones, 1990 to 1992.

During the last 2 years, the major event in the postmarketing surveillance of quinolones has been the worldwide withdrawal of temafloxacin after only 15 weeks on the USA market. The Adverse Drug Reaction (ADR) reports that led to the withdrawal have been reviewed and show that the frequency and type of ADR and serious ADR were highly unusual in comparison with other quinolones marketed in the USA (ciprofloxacin, norfloxacin and ofloxacin). The difficulty in establishing causality between drugs and ADRs is discussed. Prescription event monitoring and computerised databases are beginning to reach the size required to pick up rare ADRs but, even so, they can only establish association rather than causality. Perhaps a more important question is the issue of acceptable risk. This requires better definition in order to apply decision analysis to the options available for the treatment of bacterial infections.