A double-blind, randomized comparison of the cognitive/psychomotor and inferred driving impairment side effects of a single, mild, dose of oxycodone or placebo among elderly and young individuals

Many elderly individuals cope with acute and chronic pain by taking prescribed opioid analgesics, which have noted side effects impairing cognitive and psychomotor abilities among opiate-naive (non tolerant) individuals (Chrischilles, E., Lemke, J., Wallace, R., and Drube, G. 1990; Cooner, A., 1997; O'Neill, W., 1994; Purdue, 2001; Saarialho-Kere, U., Mattila, M., and Seppala, T.,1989; Vaino, A., Ollila, J., Matikainen, E., and Kalso, E., 1995; Walker & Zacny, 1999). The known side effects associated with opioid use may also impair driving ability among opiate-naive individuals, although no direct empirical evidence supporting this claim has yet emerged. The present placebo-controlled, double-blinded study investigated whether an average clinical dose of oxycodone causes greater cognitive/psychomotor and driving impairment among healthy, opiate-naive elderly and young persons. After completing baseline measures, young participants either received 0.10 mg/kg or 0.15 mg/kg orally administered oxycodone or placebo (n = 12 per group, mean age = 20.4 years, range = 19-25 years), whereas older participants received either 0.10 mg/kg orally administered oxycodone or placebo (n = 9 per group, mean age = 71.1 years, range = 65-81 years). Medication/placebo participants waited one hour for peak concentration levels to occur and completed posttesting measures. Consistent with predictions, the drug produced greater cognitive/psychomotor and predicted driving ability impairments among healthy, pain-free older participants than among younger participants as measured by the Trail Making Test B and the Useful Field of View tasks. A significant cognitive/psychomotor task order effect emerged among younger but not older participants, suggesting longer drug elimination times and, consequently, lingering cognitive/psychomotor side effects among elderly compared to younger individuals. No analgesic response order effects emerged for the young group, suggesting that (a) the cognitive side effects dissipate more quickly than the analgesic effects and that (b) cognitive side effects and analgesic effects have separate "pathways." Study findings suggest age-related cognitive and psychomotor response differences to oxycodone among opiate-naive individuals and demonstrate their clinical relevance.