Prescription-event monitoring and reporting of adverse drug reactions

Newly marketed drugs in the UK are marked with a black triangle, indicating that doctors should report all adverse drug reactions associated with them to the Committee on Safety of Medicines (CSM). However, under-reporting of adverse reactions is frequent. Our aim was to establish what types of adverse reactions are under-reported to the CSM by family doctors who work in England. We used prescription-event monitoring data obtained for 15 newly marketed drugs. Only 9% (376) of 4211 events found on prescription-event monitoring were reported to the CSM. However, 53% (27) of 51 events classified as serious adverse drug reactions were reported. Overall, serious events were five times more likely to be reported to the CSM than non-serious events. Our results should not be extrapolated to calculate incidence rates of adverse drug reactions in the community from spontaneous reports.