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Driving ability after acute and sub-chronic administration of levocetirizine and diphenhydramine: a randomized, double-blind, placebo-controlled trial

Joris C. Verster, A. Marit de Weert, Saskia I. R. Bijtjes, Mounir Aarab, Armand W.A.A. van Oosterwijck, Erik J. E. Eijken, Marinus N. Verbaten, Edmund R. Volkerts

Psychopharmacology, 2003

75 citations

Abstract

RATIONALE: Sedation following antihistamine use poses a danger to ambulant patients involved in daily activities such as driving.

OBJECTIVE: To investigate effects of levocetirizine (5 mg), diphenhydramine (50 mg), and placebo on driving ability during normal traffic.

METHODS: Forty-eight healthy volunteers participated in a double-blind, placebo-controlled, randomized clinical trial. Treatments were administrated on days 1, 2, 3 and 4, exactly 1.5 h before the start of the standardized driving test (performed on day 1 and day 4). In the standardized driving test, subjects were instructed to drive with a steady lateral position, while maintaining a constant speed (95 km/h). Primary parameter was the standard deviation of lateral position (SDLP; cm). Statistical analyses were performed separately for day 1 and day 4, using analysis of variance and an equivalence test. Equivalence to placebo was evidenced if the 95% confidence interval lay between -2.6 cm and +2.6 cm.

RESULTS: SDLP after levocetirizine was equivalent to placebo on both day 1 (-0.66 cm; +1.12 cm) and day 4 (-0.37 cm; +1.28 cm). In contrast, SDLP after diphenhydramine differed significantly from placebo on both day 1 ( P<0.0001) and day 4 ( P<0.0003). On day 1, the 95% confidence interval of diphenhydramine (+1.85 cm; +3.63 cm) was partially above the upper equivalence limit (+2.6 cm), indicating clinically relevant driving impairment. On day 4, however, the 95% confidence interval of diphenhydramine (+0.74 cm;…

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Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.

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