Cetirizine vs placebo in chronic idiopathic urticaria--a double blind randomised cross-over study

The efficacy of cetirizine dihydrochloride, a new H1-antagonist claimed to have minimal sedative property was evaluated in 28 patients with chronic idiopathic urticaria. Cetirizine 10 mg and placebo were compared in a double-blind cross-over trial. Response was measured by patients with daily charts on itch and wheals. Response was also assessed by patients and investigators while on cetirizine and placebo on an analogue scale. The mean analogue score by the investigator while on cetirizine (64.6 mm) was better than while on placebo (47.0 mm) (p = 0.008). Reduction of itch with cetirizine was significantly greater than with placebo. The mean itch scores for placebo and cetirizine were 21.2 and 14.5 respectively (p = 0.01) showing a significant improvement of itch by cetirizine. The mean score for wheal response for placebo and cetirizine were 21.0 and 16.16 respectively (p = 0.07 NS) showing a reduction of wheal from cetirizine was greater than placebo but the difference was not statistically significant. The patients' mean visual analogue score for placebo was 38.4 and for cetirizine was 57.5 (p = 0.006). Cetirizine was significantly better in controlling symptoms of chronic urticaria than placebo. Five of the 28 (17.9%) patients reported mild drowsiness while taking cetirizine. Two patients reported drowsiness while on placebo. Tolerance was reported as good in 85%, moderate in 10% and bad in 5% according to patients' assessment, while tolerance was excellent and good in 80%, moderate in 15% of patients according to investigator's assessment.