ALCOHOL PHARMACODYNAMICS IN YOUNG ELDERLY ADULTS CONTRASTED WITH YOUNG AND MIDDLE-AGED SUBJECTS

Effects of aging on ethyl alcohol (EtOH) pharmacodynamics were examine d over progressive dosing schedules (0.4, 0.6, 0.8, 1.0 g/kg) in group s of young (25.0+/-2.9 years), middle-aged (41.1+/-6.6 years), and you ng-elderly adults (60.9+/-2.6 years) using three computerized cognitiv e-neuromotor tasks: digit-symbol substitution (DSS), keypad reaction t ime (KRT), and subcritical tracking (SCT). Hysteresis curves of perfor mance impairment (adjusted for pre-drug baseline) as a function of blo od alcohol concentration (BAG) were examined for time-course effects, and regression analyses were performed to assess the contribution of a ge beyond that accounted for by BAG. Results reflected differences in the patterning but not magnitude of impairment for elderly subjects, w ith earlier decrements and more rapid acute tolerance observed for DSS , in conjunction with less pharmacodynamic sensitivity for SCT. Regres sion analyses furthermore indicated that age and impairment were negat ively related, arguing against synergistic intoxication effects as a f unction of aging. Analyses specifically comparing performance at basel ine versus legally intoxicating BACs (>1.0 mg/ml) likewise reflected a lack of interactive effects involving the elderly. Elderly subjects n evertheless exhibited significantly lower baseline performance for DSS and KRT than young subjects and achieved higher BACs with equivalent doses. These latter findings support the exercise of caution by elderl y individuals consuming EtOH prior to engaging in neuromotor pursuits such as driving.