Evaluation of the antihistamine effects of olopatadine, cetirizine and fexofenadine during a 24 h period: a double-blind, randomized, crossover, placebo-controlled comparison in skin responses induced by histamine iontophoresis.

Potency of the antihistamine effects of olopatadine, cetirizine and fexofenadine in standard-dose application were compared from 11.5 to 24 h after application. The test was designed in a double-blind, randomized, crossover, placebo-controlled study of ten healthy volunteers on histamine-induced flare and wheal response using an iontophoresis technique. The suppressive effect of olopatadine on the wheals induced by a 0.1-mA histamine iontophoresis lasted for 24 h after dosing. Fexofenadine administered using the same regimen was the least effective among three drugs tested. Suppression of the wheal response by cetirizine, taken once-daily, decreased with time. Olopatadine completely suppressed even the wheal response induced by a 0.2-mA histamine iontophoresis, although fexofenadine and cetirizine were less effective on the wheals induced by the same histamine challenge. There were no significant differences in subjective drowsiness and objective cognitive function between drug- and placebo-treated subjects. These results demonstrate that olopatadine is the most potent antihistamine among the three H(1)-blockers when administered in a standard dosage.

RCT Entities:   Population Interventions Outcomes