Do Drowsy Driver Drugs Differ?

This research paper explores how different drug mechanisms within a single class of drugs can produces different profiles of driving impairment. Prior research has failed to consider these mechanistic differences and often utilizes less controlled study methodologies. The potential impact of differing mechanistic effects is important for practitioners but remains unclear for most drugs. Twentynine licensed drivers in good general health completed one of two miniSim™ studies using a validated, standardized, driving impairment scenario. Both drugs caused degradation in lateral control measures of standard deviation of lane position (SDLP) and number of lane departures, however only diphenhydramine was found to cause a significant change in steering bandwidth. The studied drugs differed in their effects on all longitudinal driving measures with diphenhydramine effecting speed and alprazolam effecting the standard deviation of speed. Difference in therapeutic mechanism of action results in differing pharmacodynamic driving performance outcomes. This analysis reinforces the importance of careful consideration of a drug’s specific mechanism of action when considering a sedating drug’s impact on a patient’s ability to safely operate a motor vehicle