Gender Differences in Highway Driving Performance After Administration of Sleep Medication: A Review of the Literature

Objectives: It is generally assumed that there are minimal gender differences in the safety and efficacy of central nervous system drugs, as is evidenced by men and women receiving the same drug dosage. There is, however, evidence that drugs may have a differential effect on performance in men and women, given reported differences in pharmacokinetics as well as the presence or absence and severity of adverse effects. It is especially important to verify whether gender differences in performance exist in case of activities that have potentially dangerous outcomes such as driving a car. This review summarizes the current scientific evidence on gender differences in driving performance after treatment with hypnotic drugs. Methods: A literature search was conducted to obtain all studies that conducted on-road driving tests to examine the effects hypnotic drugs on driving. Cross-references were checked and technical reports and raw data were obtained, if possible. Results: Fourteen studies were evaluated. Many studies did not allow analyses of gender effects because only women were included. Others did not report data on gender analyses. Technical reports and additional data analyses revealed significant gender differences in driving performance the morning following bedtime administration of flurazepam (30 mg) and after middle-of-the-night administration of zolpidem (10 mg). No significant gender differences were found for ramelteon (8 mg), lormetazepam (1 and 2 mg), zaleplon (10 and 20 mg), and zopiclone (7.5 mg). Conclusions: Although the available data are limited, the results show that significant gender differences have been found for some drugs but not others. Therefore, in the future more research is needed to reveal potential gender differences and to determine what mediates them.