Dose‐ranging, placebo‐controlled study of cetirizine nasal spray in adults with perennial allergic rhinitis

A total of 360 patients with perennial allergic rhinitis were randomized in a placebo-controlled, dose-finding study comparing three concentrations (0.06%, 0.125%, and 0.25%) of a cetirizine nasal spray, administered three times a day for 2 weeks. The primary criterion of efficacy was the percentage of days with no or only mild symptoms of rhinitis (PDMax1), as evaluated by the patients. The median PDMax1 were 16.7%, 30.8%, 42.9%, and 26.7% for the placebo, 0.06%, 0.125%, and 0.25% groups, respectively. Although the global comparison among the four groups only approached statistical significance (P = 0.076), the difference (26.2%) between the placebo and 0.125% groups was clinically and statistically significant (P = 0.011). For the global evaluation by the investigator, the best results were seen in the 0.125% group (P = 0.03). The occurrence of adverse events did not differ among the four treatment groups and consisted mainly of nasal events, occurring in 22.5%, 17.1%, 12.9%, and 24.4% of the patients for the placebo, 0.06%, 0.125%, and 0.25% groups, respectively (P = 0.184). These results indicate that the 0.125% concentration is significantly better than placebo and offers the best therapeutic ratio.