A retrospective analysis was made of the nature and composition of 107 consecutive topics presented in publications by or in collaboration with the national pharmacovigilance centre in The Netherlands, containing data obtained through 'spontaneous reporting'. These tropics were published in various national and international professional journals or special bulletins or as 'dear doctor letters'. The topics constituted a wide variety of events and disorders. There was, however, a predominance of concrete, characteristic and often serious diseases, notably specific hypersensitivity reactions (43%, e.g. anaphylaxis, blood dyscrasias and liver injury), toxic manifestations or syndromes (30%, especially involving the nervous system), and drug interactions (13%). Most topics presented predominantly qualitative information. 62% of topics concerned type B, 33% type A and 3% type C adverse drug effects. The topics often referred to small numbers of case reports: 10 or less in 70% of the 107 topics. 46% of the topics concerned new information. There was some predominance of established (56%) over new drugs. Five pharmacotherapeutic groups accounted for 74% of topics. Of the 72 approved drugs or drug groups, 12 (17%) have been removed from the market. These findings increase our understanding of the functioning of pharmacovigilance and may enable further improvement of the methods and strategies involved.
