Phenytoin and Driving Safety: A Randomized, Controlled Cross-Over Study
Status:
Completed
Trial end date:
2008-12-01
Target enrollment:
Participant gender:
Summary
Automobile driving is a crucial aspect of everyday life, yet vehicular crashes represent a
serious public health problem. Patients with epilepsy are at elevated risk for automobile
crashes, causing great personal suffering and financial costs to society. Most collisions
involving epileptic drivers are not seizure related but may instead result from cognitive
effects upon driving performance of epilepsy and antiepileptic drugs (AEDs). Several million
American drivers take AEDs for treatment of medical conditions besides epilepsy and may also
be at risk for cognitive impairments that can reduce driving performance. Empirical evidence
of the effects of AEDs on driving performance would enable development of driving guidelines
that could lower the risk of injurious motor vehicle collisions; however, this evidence is
currently lacking. The broad goal of our project is to determine the specific effects of the
most commonly utilized AED, phenytoin, by assessing driving performance and cognitive
abilities in neurologically normal volunteers taking phenytoin in a randomized, double-blind,
placebo-controlled, crossover study. Our proposed experiments will assess: (1) cognitive
functions using standardized neuropsychological tests (of attention, perception, memory, and
executive functions), (2) driving performance during phenytoin and placebo administration,
and (3) the effects of phenytoin-related cognitive performance upon driving performance. To
measure driving performance, we will use a state-of-the-art fixed-base interactive driving
simulator that allows us to observe driver errors in an environment that is challenging yet
safe for the driver and tester, under conditions of optimal stimulus and response control.
The results of this study of 30 drivers treated with phenytoin and placebo will increase the
understanding of the role of AED-related cognitive impairment on driving safety errors. A
better understanding of the impact of AEDs upon driving performance is necessary to
rationally develop interventions that could help prevent crashes by drivers treated with
AEDs.