Influence of peak and trough levels of opioid maintenance therapy on driving aptitude.

To evaluate driving aptitude and traffic-relevant performance at peak and trough medication levels in opioid-dependent patients receiving maintenance therapy with either buprenorphine (mean: 13.4 mg) or methadone (52.7 mg) and a medication-free control group, the Addiction Clinic at Medical University Vienna conducted a prospective, open-label trial where 40 opioid-dependent patients maintained either on buprenorphine or methadone were assessed regarding their traffic-relevant performance. Using the standardized Act and React Testsystem (ART) 2020 Standard test battery, traffic-relevant performance was analysed 1.5 h (peak level) and 20 h (trough level) after administration of opioid maintenance therapy. Results showed that patients at trough level had a significantly higher percentage of incorrect reactions (p = 0.03) and more simple errors (p = 0.02) than patients at peak level as well as methadone-maintained patients at peak level tended to perform less well than buprenorphine-maintained patients in some of the test items, e.g. methadone-maintained patients at trough level had a higher number of delayed reactions in the RST3 phase 2 test (p = 0.09) and answered fewer questions correctly in the visual structuring ability test (p = 0.04). This investigation indicates that opioid-maintained patients did not differ significantly at peak vs.trough level in the majority of the investigated items and that both substances do not appear to affect traffic-relevant performance dimensions when given as a maintenance therapy in a population where concomitant consumption would be excluded.