Citation

Mattila MJ, Kuitunen T, Veilahti J. J. Traffic Med. 1993; 21(3): 101-114.

Copyright

(Copyright © 1993, International Association for Accident and Traffic Medicine)

DOI

unavailable

PMID

unavailable

Abstract

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 studies with 12 healthy subjects in each. In Trial I, oral single doses of lorazepam (LZ) 2 mg in two formulations and ethanol (EOH) 1 g/kg were given 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 the clinical test, LZ and EOH impaired motor and mental subtests but EOH also impaired vestibular functions. In Trial II, the mean BACs (0.82, 0.53 and 0.25 g/ml at 2, 4 and 6 h) and EOH-induced decrement of performance were less than in Trial I. Ebastine neither impaired performance nor increase EOH effects. As to the clinical test, significant drug effects due to EOH or ebastine + EOH were seen only in vestibular and motor subtests at 2 h but not at 5 h. We conclude that the two LZ formulations are similar in practice; LZ 2 mg is more detrimental than 1 g/kg EOH in laboratory tests but not in the clinical test; and the empirically chosen 'global test' might be useful when comparing the decrements of performance caused by drugs and alcohol.

Keywords

Drug impaired driving; Ethanol impaired driving