Cognitive, coordinative and reactive functions, separately and combined to a "global test", and the clinical test for drunkenness were compared in two placebo-controlled double-blind crossover studieswith 12 healthy subjects in each. In Trial I, oral single doses of lorazepam (LZ) 2 mg in two formulations and ethanol (EOH) 1g/kg weregiven in balanced order. In Trial II, EOH (0.8 g/kg) was given during the treatment with an H1-antihistamine ebastine (20 mg daily) or placebo. Performance was tested before and after the intake of the drugs. LZ given in capsules or sublingual tablets similarly caused drowsiness, mental slowness and clumsiness, and impaired cognitive (digit substitution), reactive and coordinative (simulated driving) performances at 2, 4 and 6 h after intake. Mean blood alcohol concentrations (BACs) were 1.27, 0.92 and 0.61 g/l at 1.5, 3.5 and 5.5 h after EOH which much resembled LZ in its effects, with some qualitative (drowsiness, body sway) differences. The "global effect" (tracking error severity + 10 reaction time / digits substituted) provided a single variable for the comparison of LZ and EOH, its justification being confirmed by the subsequent G-test computed for the same variables. In clinical test, LZ and EOH impaired motor and mental subtests but EOH also impaired vestibular functions.
Abstract