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.