ACRIVASTINE, TERFENADINE AND DIPHENHYDRAMINE EFFECTS ON DRIVING PERFORMANCE AS A FUNCTION OF DOSE AND TIME AFTER DOSING

The study was conducted according to a nine-way, observer- and subject -blind, cross-over design. Its purpose was to compare the single-dose effects of the following drugs on driving performance: acrivastine (8, 16 and 24 mg); the combination of acrivastine (8 mg) with pseudoephed rine (60 mg); terfenadine (60, 120 and 180 mg); diphenhydramine-HCl (5 0 mg); and placebo. The subjects were 18 healthy female volunteers. Dr ug effects were assessed in two repetitions of two driving tests (high way driving and car-following) after each treatment. Acrivastine's imp airing effects in bath driving tests were similarly dose-related. The 8-mg dose had a small, but significant, effect on highway driving in t he first trial. The 16-mg and 24-mg doses significantly impaired drivi ng in both tests during the first trial and the 24-mg dose did so agai n during the second trial. Neither the combination of acrivastine with pseudoephedrine nor terfenadine caused any significant impairment of performance. Diphenhydramine significantly impaired driving in both te sts during every trial. In conclusion, the normal therapeutic dose of acrivastine (8 mg) had little effect on driving performance, and virtu ally none when that dose was given in combination with pseudoephedrine (60 mg). Higher doses of acrivastine severely impaired driving perfor mance. Terfenadine had no significant effect on driving performance af ter any dose while diphenhydramine strongly impaired every important d riving parameter.