An investigation into the effects of cetirizine on cognitive function and psychomotor performance in healthy volunteers

Objective: The cognitive and psychomotor effects of 2.5, 5 and 10 mg cetiri zine, a second-generation H-1 receptor antagonist, were compared with lorat adine 10, 20 and 40 mg, promethazine 25 mg and placebo in 24 healthy Volunt eers in a double-blind, randomised cross-over study. Methods. Following each dose, subjects were required to perform a series of tests of cognitive function and psychomotor performance at 1.5, 3 and 6 h post-dose. The test battery consisted of critical flicker fusion (CFF), cho ice reaction time (CRT), compensatory tracking task (CTT) and assessment of subjective sedation (LARS). Results: Cetirizine and loratadine at all doses tested were not significant ly different from placebo in any of the tests used. However, as expected fo r a verum, all measures with the exception of CTT were significantly disrup ted by promethazine (P < 0.05). Promethazine caused a reduction in CFF thre shold at all test points; these differences were significant at 3h and 6h p ost-dose (P < 0.05). There was also a significant increase in total reactio n time at 3 h post-promethazine administration. Subjective reports of sedat ion were significantly greater following the administration of promethazine at all time points (P < 0.05). Conclusions: These results allow the conclusion that cetirizine at its reco mmended therapeutic dose of 10 mg is demonstrably free from disruptive effe cts on aspects of psychomotor and cognitive function in a study where the p sychometric assessments have been shown to be sensitive to impairment, as e videnced by the effects of the positive control, promethazine 25 mg.