A controlled, double-blind study of the effect of quazolast on nasal challenge with ragweed antigen

Quazolast is a potent mediator release inhibitor as determined by in vitro and in vivo testing. A placebo-controlled, double-blind, two-way crossover study compared the safety and efficacy of Quazolast, 400 mg bid orally, with placebo in 23 subjects with ragweed (RW) allergy, out of season. Subjects were assigned to two 7-day treatments in a random sequence with an 8-day washout. Subjects were challenged on days 1 and 7 of each trial with serial dilutions (10, 100, 1000, 1350, and 2700 PNU/0.135 mL) of RW, using metered pump spray bottles, (two sprays delivered 0.135 mL), preceded by saline control. Efficacy evaluation consisted of nasal flow rates measured by rhinomanometry, sneeze counts, nasal itchiness scores, and weight of nasal secretions during challenges. During Quazolast treatment, subjects had significantly lower (P less than .05) mean percent decreases in nasal flow rate at 1350 and 2700 PNU. Nasal itchiness scores were significantly lower (P less than .05) during Quazolast treatment than at placebo at 1000, 1350, and 2700 PNU. Although sneeze counts were lower during treatment with Quazolast than with placebo, the results did not reach statistical significance. No significant improvement was seen in the weight of nasal secretions. Adverse experiences, clinical laboratory results, and physical examinations were unremarkable, posttreatment. Quazolast was superior to placebo in protecting against nasal congestion and nasal itchiness after ragweed nasal challenge.