Opioid dependence and driving ability: a review in the context of proposed legislative change in Victoria

There is debate in Victoria, Australia concerning the effects of various drugs, including opioids, on driving skills and accident rates, and the development of appropriate legislative responses. There are legislative difficulties around drugs and driving because of the lack of adequate epidemiological and performance-based studies. In relation to opioids, although there are studies that have shown the prevalence of opioids in both non-fatal and fatal crashes, these studies do not demonstrate that the use of opioids is associated with any elevated crash risk and they fail to take into account issues regarding tolerance. A review of the performance studies, including only a small number of driving studies, suggests that opioids, and in particular methadone, have limited effects on driving skills. None the less, recommendations have been made in other countries, such as Germany, that place driving restrictions upon methadone clients. This paper reviews the available evidence concerning the effects of opioids on driving skills and accident risk, with reference to the proposed changes to legislation in the area of drugs and driving in Victoria.