Purpose: One of the main methods for monitoring the safety of marketed drugs is spontaneously reporting of suspected adverse drug reactions (ADRs). The objective of this study was to describe the pattern of spontaneously reported fatal adverse drug reactions (FADRs) by analysing data from the national spontaneous reporting system in Sweden.
Methods: In Sweden it is compulsory to report all new or serious suspected ADRs to the Medical Products Agency. The information in these reports is stored in the national database SWEDIS (Swedish Drug Information System). All suspected FADRs reported to SWEDIS between 1 January 1995 and 31 December 2004 were reviewed and analysed.
Results: During the study period 990 reports of FADRs were found. The main distribution of suspected FADRs was: haemorrhages (n = 603; 60.9%), blood and bone marrow dysfunction (n = 71; 7.2%), sudden death (n = 38; 3.8%) and pulmonary embolism (n = 30; 3.0%). Antithrombotic agents were the drugs most frequently implicated in the FADRs (n = 605; 61.1%). Vitamin K antagonists were reported in 453 cases (45.8%) and acetylsalicylic acid in 82 cases (8.3%). Among the fatalities with blood and bone marrow dysfunction methotrexate was the most frequently reported drug. For sudden death and pulmonary embolism, antipsychotics and oestrogen containing drugs, respectively, were most commonly reported.
Conclusions: Bleeding complications amounted more than half of all reports of FADRs and vitamin K antagonists were implicated in most of these reports. However, as spontaneous reporting systems are primarily set up for signalling purposes, the data must be interpreted with utmost care.