Double dose of cetirizine hydrochloride is effective for patients with urticaria resistant: a prospective, randomized, non-blinded, comparative clinical study and assessment of quality of life.

An increased dose of the prescribed drug or a change of the drug is recommended in the treatment for the patients with urticaria refractory to the standard dose of antihistamines. Efficacy and safety of doubling the dose of cetirizine were compared with olopatadine in the patients with symptoms like wheal or itching, despite the treatment with the standard dose of cetirizine. Cetirizine was administered at 10 mg once daily to 51 patients with urticaria for a mean of 10.1 ± 7.3 days (period A). Patients with inadequate responses were randomized to either cetirizine 20 mg once daily (dose-increase group) or olopatadine 5 mg twice daily (drug-change group) for a mean of 13.3 ± 8.3 days (Period B). The severity of wheal and itching, and the quality of life (QOL) measured by Skindex-16 were evaluated. In period A, an adequate response was obtained in 64.7% (33/51). Nine patients each with inadequate response were randomized to either the drug-change or dose-increase groups. A significant improvement was observed in the severity of wheal and itching in the dose-increase group in period B. The QOL was significantly improved in all sub-scales of Skindex-16. Doubling the dose of cetirizine may be efficacious to the patients with urticaria refractory to the regular dose of cetirizine.