Intravenous Cetirizine Non-Inferior to IV Diphenhydramine for Acute Urticaria

November 4, 2019

By Erik MacLaren

DENVER -- November 2, 2019 -- Intravenous (IV) cetirizine is non-inferior to IV diphenhydramine in the treatment of acute urticaria and has a better safety profile, according to a study presented here at the 2019 Annual Meeting of the American College of Emergency Physicians (ACEP).

Benjamin Abella, MD, University of Pennsylvania, Philadelphia, Pennsylvania and colleagues randomised 262 adult patients with acute urticaria who presented to 1 of 19 EDs or urgent care centres from March 2017 to April 2018 to receive either IV diphenhydramine 50 mg or IV cetirizine 10 mg.

The primary endpoint was the change in pruritus score from baseline to 2 hours after treatment. The pruritus score fell 1.61 in the cetirizine group and 1.50 in the diphenhydramine -- a difference that was not statistically significant, demonstrating non-inferiority.

Among the secondary endpoints, the investigators found significantly less sedation in patients in the cetirizine group up to 2 hours after treatment (P = .0292) and at ED discharge (P = .0443).

The rate of adverse events (AEs) was also lower in the cetirizine group (4%) than the diphenhydramine group (13%; P = .0083), and the most commonly reported AEs were dizziness and nausea, which were only reported by subjects in the diphenhydramine group.

The researchers also reported fewer uses of rescue drug among patients treated with cetirizine (P = .0159), as well as significantly less time in the ED (1.7 vs 2.1 hours; P = .0024) and returns to the ED (5.5% vs 14.0%; P = .0232).

“This finding was unexpected,” said Dr. Abella, when asked about the returns to the ED.

However, he noted that reduced time spent in the ED and reduced rates of return would have benefits to ED efficiency above and beyond the clinical benefit to patients that the study documented.

Funding for this study was provided in part by JDP Therapeutics.

[Presentation title: IV Cetirizine Versus IV Diphenhydramine in Treatment of Acute Urticaria. Abstract 310]