The Effect of Cetirizine on Nasal Allergic Response

Abstract

The effect of cetirizine on both early and late nasal allergic response was assessed in 15 ragweed sensitive patients. All patients were challenged before treatment and after 7 days of cetirizine 10 mg qd. Clinical assessments and measurements of mediators were performed at baseline, after positive challenge, 1 and 2 hours later, and repeated 7 and 8 hours later. There was a significant change (P < 0.0001) in the early response threshold to ragweed challenges after cetirizine. There were early phase elevations of prostaglandin D₂, leukotriene C₄, and eosinophil cationic protein both pre and post-treatment. Late phase changes were difficult to detect, but a statistically significant rise of both prostaglandin D₂ and histamine was diminished after cetirizine treatment. Cetirizine clinically inhibited the early response to nasal allergen challenge, but early mediators were not affected. An effect on the late phase could not be clearly demonstrated.