Olopatadine hydrochloride for the treatment of chronic idiopathic urticaria: a multicentre, double-blind, randomized, parallel-group, controlled clinical trial

Objective To evaluate the efficacy and safety of olopatadine hydrochloride for the treatment of chronic idiopathic urticaria (CIU). Methods A multicentre, double-blind, randomized, parallel-group, controlled clinical trial was conducted. A total of 144 patients with CIU from 3 research centers were enrolled into this study, and randomly and equally divided into a test group and a control group. The test group administrated olopatadine hydrochloride 5 mg twice a day for 28 consecutive days, while the control group administrated levocetirizine hydrochloride 5 mg in the forenoon and a placebo tablet of olopatadine hydrochloride 5 mg in the afternoon for 28 consecutive days. The symptom score reducing index (SSRI) served as the primary outcome, and global assessment score for efficacy and total response rates as the secondary outcome. Results Totally, 137 patients completed the trial, including 70 in the test group and 67 in the control group. As intention-to-treat analysis showed, there were no significant differences in the total response rate between the test group and control group on day 7 (64.29% (45/70) vs. 56.72% (38/67), P> 0.05), 14 (82.86%(58/70) vs. 74.63%(50/67), P> 0.05), or 28 (87.14% (61/70) vs. 77.61% (52/67), P> 0.05) after start of treatment. The SSRI was significantly higher in the test group than in the control group after 4 weeks of treatment (82.67% ± 22.70% vs. 70.51% ± 32.07%, P 0.05), and adverse reactions mainly included lethargy, dry mouth, fatigue, etc. Conclusion Olopatadine hydrochloride is effective and safe for the treatment of CIU. Key words: Urticaria; Randomized controlled trial; Olopatadine; Levocetirizine