Multicenter, crossover study of the efficacy and tolerability of terfenadine, 120 mg, versus cetirizine, 10 mg, in perennial allergic rhinitis.

In this 3-week randomized, double-blind, double-dummy multicenter, crossover study terfenadine, 120 mg, was compared with cetirizine, 10 mg, both given once daily in the treatment of perennial allergic rhinitis in sixty patients. Compared with the investigators' pretreatment assessment, both terfenadine and cetirizine significantly reduced the severity of all five symptoms (P less than .001). The two treatments were equally effective in controlling eye irritation, sneezing, nasal congestion and itchy nose, throat and palate, but cetirizine improved rhinorrhea more than terfenadine (P less than .05). Daily symptom assessments by the patients for the last 14 days of each treatment period showed no difference in efficacy between the two drugs for any of the symptoms. There were also no differences between the two drugs for overall assessments of efficacy or patient preference. Adverse events were recorded more frequently while taking cetirizine, with 14 attributable events compared with only five with terfenadine. Four of the cetirizine-related events were drowsiness or tiredness, but none was reported while patients were taking terfenadine. There was a tendency to increased weight (greater than 1 kg) with both treatments.