Prescription Medicines and the Risk of Road Traffic Crashes: A French Registry-Based Study

Using three nationwide databases in France, Ludivine Orriols, Emmanuel Lagarde, and colleagues provide evidence that prescribed medicines contribute to the risk of experiencing a road traffic crash.Background: In recent decades, increased attention has been focused on the impact of disabilities and medicinal drug use on road safety. The aim of our study was to investigate the association between prescription medicines and the risk of road traffic crashes, and estimate the attributable fraction. Methods and Findings: We extracted and matched data from three French nationwide databases: the national health care insurance database, police reports, and the national police database of injurious crashes. Drivers identified by their national health care number involved in an injurious crash in France, between July 2005 and May 2008, were included in the study. Medicines were grouped according to the four risk levels of the French classification system (from 0 [no risk] to 3 [high risk]). We included 72,685 drivers involved in injurious crashes. Users of level 2 (odds ratio [OR] = 1.31 [1.24–1.40]) and level 3 (OR = 1.25 [1.12–1.40]) prescription medicines were at higher risk of being responsible for a crash. The association remained after adjustment for the presence of a long-term chronic disease. The fraction of road traffic crashes attributable to levels 2 and 3 medications was 3.3% [2.7%–3.9%]. A within-person case-crossover analysis showed that drivers were more likely to be exposed to level 3 medications on the crash day than on a control day, 30 days earlier (OR = 1.15 [1.05–1.27]). Conclusion: The use of prescription medicines is associated with a substantial number of road traffic crashes in France. In light of the results, warning messages appear to be relevant for level 2 and 3 medications and questionable for level 1 medications. A follow-up study is needed to evaluate the impact of the warning labeling system on road traffic crash prevention. : Please see later in the article for the Editors' Summary Editors' Summary: About 1.3 million people die each year on the world's road. 90% of road traffic deaths occur in developing countries, with pedestrians, cyclists, and users of two-wheel vehicles (scooters, motorbikes) the most vulnerable road users. Although the use of prescribed benzodiazepines has already been documented to be associated with road traffic accidents in industrialized countries, the effects of other medicines have not been well studied or have inconsistent results (for example opioids and antidepressant medications). In the European Union, it is mandatory for pharmaceutical companies to provide data about the effect of a medicine on ability to drive. In France, a multidisciplinary group of experts was appointed to classify all medicines into four levels of risk (from level 0, no or negligible risk, to level 3, major risk), in terms of their effect on driving performances. In 2006, the International Council on Alcohol, Drugs and Traffic Safety proposed a classification list similar to the French classification system.