Effects of azatadine maleate on subjective appraisal and psychomotor functions relevant to driving performance.

Studies were carried out in normal healthy male subjects to assess the effects on psychomotor functions and subjective ratings of performance after acute administration of azatadine maleate, a potent antihistamine with additional antiserotonin activity. In the first trial, 2 mg azatadine was compared with another new antihistamine Sch 12169 (2 mg) and placebo. In a second trial, higher doses of azatadine (4 mg and 8 mg) were compared with dexchlorpheniramine (4 mg) and placebo. Both trials were of a double-blind, randomized Latin square design and subjects were assessed using a battery of tests, after administration of each trial drug. The time and sequence of tests were standarized, with a 1-week interval between test sessions. The results showed that azatadine did not produce significant impairment of psychomotor function at either the standard 2 mg or the maximum recommended 4 mg per day dosage level. Permormance was only significantly impaired, compared with that after placebo, at the 8 mg dose level and was of a similar order to that observed after dexchlorpheniramine at the usual 4 mg dosage. It is suggested, therefore, that at the normal recommended dosage of 2 mg per day, azatadine is not likely to impair driving ability.