Objectives: To review the reports of fatal adverse drug reactions (ADRs) submitted to the Ontario Medical Association Adverse Drug Reactions Monitoring Program between 1990 and 1994; to identify drugs associated with fatal outcomes; and to assess the causative role of the drug in these events and the completeness of the data in these reports.
Methods: Drug(s) identified on each ADR report as being responsible for the reaction were considered. Agents were classified by the Anatomical Therapeutic and Chemical classification system. The causality of each ADR report was evaluated by using an algorithmic rating scale.
Results: From the Ontario Medical Association database, 97 cases of ADRs that resulted in death were reviewed. One hundred fourteen medications were implicated as "suspect" drugs in the 97 deaths. The most commonly implicated drug classes were musculoskeletal agents, blood and blood-forming organ agents, and nervous system agents. Patients over 65 years of age comprised 60% of this series. After independent assessment as to causality, 13% of the cases were rated as probable, 86% were rated as possible and 1% were rated as doubtful. Seventy per cent of reports did not include information regarding medical history. Forty-two per cent of cases failed to provide adequate information to evaluate the feasibility of the time to onset of the ADR. The use of concomitant drugs was not reported in 12% of cases.
Conclusions: The drugs most frequently implicated in fatal ADRs were consistent with those reported in other studies. Algorithmic causality assessments were of limited value in these reports. The completeness of the reports and adequacy of the information were poor. The type of reporting forms and information provided were not homogenous. There is a need to improve quality of reporting and harmonize reporting forms between monitoring bodies. The feasibility of unique data collection forms and obligatory reporting for fatal ADRs should be considered.