Introduction

The 2007 National Roadside Survey found that the prevalence of drugs in weekend nighttime drivers in the USA was 16.4%—higher than 12.3% who tested positive for alcohol—bringing attention to the large potential for drugged driving.1 Research and public attention related to drugged driving was stimulated by the Office of National Drug Control Policy in its 2010 National Drug Control Strategy, encouraging all states to enact per se drugged driving laws.2 National attention on drugged driving led to calls for the testing for drugs as well as alcohol of all drivers arrested for suspicion of impaired driving.3 Wider use of drug testing has facilitated the recent development of more sensitive on-site drug tests which police officers can use at the station house or at the roadside to immediately test drivers for recent drug use.3 These factors suggest that there will be a significant increase in the numbers of individuals identified, prosecuted and convicted of drugged driving. This article focuses on the impact of this trend on prescribed medicines and how their identification among drivers can be successfully managed under traditional impairment and per se drugged driving laws.

The prevalence of prescribed controlled substances among drivers has been well-documented among fatally injured drivers, drivers involved in crashes, and drivers suspected of driving under the influence (DUI); among these groups, particular attention has been paid to the potential impairing effects on driving of benzodiazepines and z-hypnotics, marijuana, central nervous system stimulants, gamma-hydroxybutyrate (GHB), hallucinogens and opioids.4 ,5 There remains a current need for new research on the impairing effects of prescription drugs on driving.6

DUI of prescription drugs must consider four categories of drug use: (1) drivers who use prescribed controlled substances only as directed by their physician and not in combination with alcohol or …