Prescription medication use and crash risk: taking responsibility for a new global challenge
Authors: Luke A Downey, Amie C Hayley
Journal: The Lancet Public Health (2021)

Each year over 1·3 million people are killed, and between 20 and 50 million more sustain life-changing injuries due to road traffic collisions.1WHOGlobal status report on road safety.https://www.who.int/violence_injury_prevention/road_safety_status/2018/enDate: 2018Date accessed: March 2, 2021Google Scholar Road trauma accounts for a considerable proportion of global macroeconomic and health burden; much of which is unequally distributed, and disproportionally borne by low-income and middle-income regions.2Chen S Kuhn M Prettner K Bloom DE The global macroeconomic burden of road injuries: estimates and projections for 166 countries.Lancet Planet Health. 2019; 3: e390-e398Summary Full Text Full Text PDF PubMed Scopus (51) Google Scholar With many contributors to collision causality being potentially modifiable through changes to infrastructure, policy, car manufacturing, and driver behaviour, the responsibility for crash avoidance should be a shared proposition for the global community of road users. Impaired driving due to psychoactive substance usage remains one of the largest preventable contributing factors to road trauma statistics worldwide.1WHOGlobal status report on road safety.https://www.who.int/violence_injury_prevention/road_safety_status/2018/enDate: 2018Date accessed: March 2, 2021Google Scholar Enactment and enforcement of best-practice legislative policies to reduce road traffic deaths due to drink-driving (eg, legal blood alcohol concentration) have successfully reduced alcohol-related harm in the past few decades.3Mann RE Macdonald S Stoduto LG Bondy S Jonah B Shaikh A The effects of introducing or lowering legal per se blood alcohol limits for driving: an international review.Accid Anal Prev. 2001; 33: 569-583Crossref PubMed Scopus (131) Google Scholar However, the proportion of drivers involved in traffic collisions that are intoxicated by psychoactive drugs continues to increase.4Hedlund J Macek K Drug-impaired driving: marijuana and opioids raise critical issues for states.http://www.ghsa.org/resources/DUID18Date: 2018Date accessed: March 2, 2021Google Scholar Enforcement strategies designed to mitigate drug-affected driving primarily concern the detection of illicit substances as determined by region-specific legal frameworks of zero-tolerance, impairment-based, or per se approaches (eg, checking in body substance concentration against legal thresholds, regardless of impairment, through oral fluid tests or sobriety checkpoints).5WHODrug use and road safety: a policy brief.https://www.who.int/substance_abuse/drug_use_road_safety/en/Date: 2016Date accessed: March 2, 2021Google Scholar Despite a comparable rise, to illicit drug use, in the proportion of drivers using prescription pharmaceutical medications that have the potential to negatively affect driving ability, methods used to manage and mitigate collision risk among people who use potentially impairing—but legal—prescription medications remain underdeveloped. Jeffrey Brubacher and colleagues' robust pharmacoepidemiological study6Brubacher JR Chan H Erdelyi S Zed PJ Staples JA Etminan M Medications and risk of motor vehicle collision responsibility in British Columbia, Canada: a population-based case-control study.Lancet Public Health. 2021; (published online April 19.)https://doi.org/10.1016/S2468-2667(21)00027-XSummary Full Text Full Text PDF PubMed Scopus (5) Google Scholar published in The Lancet Public Health estimates that 119 370 (2·84%) of 4 200 000 British Columbian drivers, Canada, involved in incident collisions have an active prescription for a potentially-impairing medication. Drivers who were currently using certain prescription medications were at moderately higher odds of being at-fault for a collision compared with those without an active prescription and also with people who had previously been prescribed these medication; these higher odds persisted among long-term users. Perhaps unsurprisingly, this coincides with consumption patterns of medications identified as the most prevalent and impairing. In the same cohort, a previous study found that 3 million drivers filled approximately 46 million prescriptions for opioids reflecting a three-fold increase in consumption among active drivers over the 20-year period from 1997–2016; corresponding with a proportional increase in opioid-positive drivers involved in traffic collisions.7Staples JA Erdelyi S Moe J Khan M Chan H Brubacher JR Prescription opioid use among drivers in British Columbia, 1997-2016.Inj Prev. 2021; (published online Jan 13.)http://dx.doi.org/10.1136/injuryprev-2020-043989Crossref PubMed Scopus (1) Google Scholar Although Brubacher and colleagues' approach is comprehensive, it does not allow for detailed investigation of prescribed dose, and thus we are unable to interpret the magnitude of risk. Moreover, this design does not capture non-medical or concomitant substance use. As many as 2·4% of Canadian drivers involved in major vehicle trauma have detectable concentrations of these potentially impairing prescription medications in their bloodstream, in addition to alcohol, at the time of the traffic crash.8Brubacher JR Chan H Martz W et al.Prevalence of alcohol and drug use in injured British Columbia drivers.BMJ Open. 2016; 6e009278Crossref PubMed Scopus (33) Google Scholar This finding raises the question as to whether these drivers are unaware, or else unappreciative, of the potential risk that these substances have upon driving. Evidently, there is a disconnect between existing prescribing practices, perceived collision risk, and road safety strategies intended to reduce harm due to the use of these common but potentially impairing medications. Brubacher and colleagues place the onus of responsibility on health-care providers to counsel patients to refrain from driving while impaired. However, the burden of collisions due to medication use cannot simply be addressed by single interventions such as requesting medical doctors to further explain the significance of their potentially deleterious effects on driving. This issue is multifaceted and needs to be equally prioritised by policy makers, law enforcement, vehicle manufacturers, and the drivers themselves. While millions of trips are completed safely and without incident by drivers consuming medications or legal levels of alcohol, mounting epidemiological evidence, culpability analyses of accidents causing injury and death, as well as on-road and simulated driving studies concerning medication usage all indicate that commonly prescribed drugs can impair driver's ability to safely control their car, contributing to their disproportionate representation in road traffic collisions. 9Robertson RD Mainegra Hing M Pashley CR Brown SW Vanlaar WGM Prevalence and trends of drugged driving in Canada.Accid Anal Prev. 2017; 99: 236-241Crossref PubMed Scopus (32) Google Scholar Impaired driving that causes injury or death is a global concern that will only deteriorate if no practical steps are taken to resolve it. One example of a novel approach seeks to establish a biometric framework for indexing impairment based on characteristic standards of altered neurobehaviour due to psychoactive substance usage. In this instance, the co-development of sophisticated vehicle safety systems capable of monitoring and indexing eye movement behaviour and other physiological markers pertinent to operator behaviour show potential for helping to infer driver impairment due to medication usage.10Hayley AC Shiferaw B Downey LA Amphetamine-induced alteration to gaze parameters: a novel conceptual pathway and implications for naturalistic behavior.Prog Neurobiol. 2020; 19101929Google Scholar These approaches might help to bridge current gaps in government, law enforcement, and road-safety initiatives concerning the use of potentially impairing medications and drug combinations by identifying drivers who are at risk of a collision and could allowing drivers to identify their own impairment before becoming another road crash statistic. ACH reports a grant from Rebecca L Cooper Foundation (Al and Val Rosenstrauss Fellowship [F2021894]) during the conduct of the study. LAD declares no competing interests. Medications and risk of motor vehicle collision responsibility in British Columbia, Canada: a population-based case-control studyDrivers prescribed benzodiazepines or high-potency opioids are at increased risk of being responsible for collisions and this risk does not decrease over time. Several other classes of medications are associated with increased risk, but this association might be independent of medication effect. These findings can guide medication warnings and prescription choices and inform public education campaigns targeting impaired driving. Full-Text PDF Open Access