Prescription-event monitoring. A preliminary study of benoxaprofen and fenbufen.

Prescription-Event Monitoring (PEM) has been established at the Drug Surveillance Research Unit of the University of Southampton as a low-cost technique for ascertaining the pattern of events, whether drug-related or not, in large general practice cohorts. The reporting of "events" without the need for an opinion about the probability that they may be adverse drug reactions (ADRs) removes much of the uncertainty inherent in voluntary ADR reporting systems. Numerators (adverse events) and denominators (the number of prescriptions), enable estimates of incidence to be derived from the data. Where related drugs are studied concurrently, differences in the pattern of events may signal important differences in their safety or efficacy . A successful large-scale preliminary exercise involving nearly 9 000 doctors and 16 000 patients is described.