IV cetirizine better than IV diphenhydramine in acute urticaria

A new study finds that intravenous (IV) cetirizine is a better alternative to IV diphenhydramine for the treatment of acute urticaria.

The study, presented at the 2018 Annual Scientific Meeting of the American College of Allergy, Asthma, and Immunology (ACAAI) in Seattle, demonstrated that the use of IV cetirizine was associated with multiple benefits, including less adverse events and less symptom recurrence.

Diphenhydramine, a first-generation antihistamine that is short in duration and causes sedation, anticholinergic effects, and drug interactions is the only currently available H1-antihistamine injection.

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In this phase 3 multi-center, parallel-group, randomized, double-blind, active-controlled clinical trial, researchers compared diphenhydramine injection 50 mg/mL with a newly developed cetirizine 10 mg/mL injection for the treatment of the most common allergic reaction symptom: acute urticaria.

Study participants (N=262) were randomly assigned to an IV diphenhydramine group or to an IV cetirizine group, with a primary efficacy endpoint of change from baseline in 2-hour pruritus score. Secondary endpoints were time spent in the treatment center and the need to return to the treatment center within 48 hours. Patient sedation scores were determined at 1 hour, 2 hours, and at discharge.

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Key Findings:

• The change from baseline in 2-hour pruritus score was shown to be statistically noninferior from IV cetirizine to IV diphenhydramine, in favor of IV cetirizine.


• The participants treated with diphenhydramine spent an average of 2.07 hours in the treatment center compared with 1.71 hours spent by participants treated with cetirizine, and 14% of the participants treated with diphenhydramine returned to the treatment center within 48 hours compared with 5.5% of the group treated with cetirizine.


• The cetirizine group experienced significantly less sedation at 1 hour, 2 hours, and at discharge compared with the diphenhydramine group.

"IV cetirizine is an effective alternative to IV diphenhydramine in the treatment of acute urticaria with benefits of less sedation, less AE, earlier discharge, less symptom recurrence, and fewer return[s] to the treatment center.” concluded the authors.