A method for post-marketing screening of adverse reactions to drugs: initial results

The FDA is pilot-testing a methodology for signaling previously unsuspected relationships between drugs and important adverse events. This method uses data it receives through the FDA spontaneous reporting program. Reviewing drugs used primarily on an outpatient basis, this screening methodology focuses on "tracer" adverse events and the organization of these reactions into body/functional systems. This review process enables a clinical evaluator to perceive more easily the clinically important drug-adverse event patterns. The method can incorporate drug use data; this enables a drug's proportional share of specific adverse events, relative to its therapeutic class, to be compared to its respective proportional share of drug use. The assumption is that the adverse event distribution of drugs in a therapeutic class should be the same as the distribution of drug use in that class, if all drugs in the class were to carry the same risk. Actual examples of drug-adverse event associations signaled by the screening method are presented. The potential uses of this methodology in other settings, and under other data situations, are discussed.