Risk of road traffic accidents associated with the prescription of drugs: A registry-based cohort study

PURPOSE: The aim of this Study was to examine the risk of a car driver being involved in a road traffic accident while using prescribed drugs. We used data from population-based registries. METHODS: Information on prescriptions, road traffic accidents, and emigrations/deaths was obtained from population-based registries. The incidence of accidents in the exposed person-time was compared with the incidence in the unexposed person-time, by the standardized incidence ratio (SIR). All Norwegians ages 18-69 between April 2004 and September 2005 (3.1 million), were included in the study. RESULTS: A total of 13,000 road traffic accidents with personal injuries were registered. The risk of being involved in an accident was somewhat increased in users of prescribed drugs in the first seven days after the date of dispensing (SIR for both sexes combined = 1.4; 95% confidence interval: 1.3-1.5). The risk was markedly increased in users of natural opium alkaloids (2.0; 1.7-2.4), benzodiazepine tranquillizers (2.9; 2.5-3.5), and benzodiazepine hypnotics (3.3; 2.1-4.7). Somewhat increased or unchanged SIRs were found for nonsteroidal antiiflammatory drugs 0.5; 1.3-1.9), selective beta-2-adrenoreceptor agonists (i.e., antiasthmatics, 1.5; 1.0-2.1), calcium receptor antagonists (0.9; 0.5-1.5), and penicillin (1.1; 0.8-1.5). CONCLUSIONS: The increased risk of being involved in a road accident as driver while receiving prescribed opiates and benzodiazepines supported the results from other Studies.