Abstract
Infusion-related reactions (IRRs) are a recognized concern for chemotherapy, biologic agents, and newer immunotherapies. Antihistamines are frequently recommended to prevent or manage these reactions. For over 60 years, diphenhydramine has been the only H(1) antihistamine for intravenous (IV) administration. It has been considered the standard of care as part of premedication regimens to prevent IRRs associated with these therapies despite the lack of a US Food and Drug Administration (FDA)-approved indication and no evidence of efficacy data. Intravenous cetirizine was approved in 2019 for acute urticaria treatment, making it the only second-generation H(1) antihistamine that can be administered intravenously. Compared with diphenhydramine, cetirizine has an improved safety profile with less sedation, fewer contraindications, lower incidence of anticholinergic side effects, and minimal risk of adverse events in elderly patients. A head-to-head study demonstrated that IV cetirizine is as effective as IV diphenhydramine in reducing IRRs and may decrease chair time, treatment center visits, and the need for rescue medication. Over the past 3 decades, the FDA has addressed the issue of IRRs by mandating language regarding the requirement or recommendation for premedication in the label of over 50 FDA-approved infusion products. As more therapeutics have premedication required or recommended, IV cetirizine should be considered an antihistamine for preventing and treating IRRs. In this article, we describe a patient whose IRR was successfully managed with IV cetirizine and discuss first- vs. second-generation H(1) antihistamines and their use in treating and preventing IRRs.