Fexofenadine is the hydrochloride salt of terfenadine's active metabolite. Fexofenadine's effects on performance were assessed in this study for the purpose of determining its safety of use by patients who engage in potentially dangerous activities, especially car driving. Fexofenadine was administered in daily doses of 120 or 240 mg, each in single and divided units given over 5 days. Two milligrams of clemastine given twice daily and placebo were given in similar series. Twenty-four healthy volunteers (12 men, 12 women; age range, 21 to 45 years) participated in a double-blind six-way crossover study. Psychomotor tests (critical tracking, choice reaction time, and sustained attention) and a standardized actual driving test were undertaken between 1.5 to 4 hours after administration of the morning dose on days 1, 4, and 5 of each series. On day 5, subjects were challenged with a moderate alcohol dose before testing. Fexofenadine did not impair driving performance. On the contrary, driving performance was consistently better during twice daily treatment with 120 mg fexofenadine than during treatment with placebo, significantly so on day 4. Both of the 240 mg/day regimens significantly attenuated alcohol's adverse effect on driving on day 5. Effects in psychomotor tests were not significant, with the exception of the critical tracking test in which the first single doses of fexofenadine, 120 and 240 mg, had significantly impairing effects. It was concluded that fexofenadine has no effect on performance after being taken in the recommended dosage of 60 mg twice daily. (Author/publisher)
Abstract