The Efficacy and Safety of Continuous Intravenous Infusion of Low-dose Epinephrine in Patients with Severe Acute Urticaria Who Do Not Achieve Sufficient Responses to Conventional Treatments: An 8-year Retrospective Study

Jeong, Woo Seok; Hwangbo, Hyun; Lee, Sook Kyung

Abstract

BACKGROUND
Acute urticaria sometimes accompanies severe systemic reactions that can be potentially life-threatening. Some patients do not achieve sufficient responses to conventional treatments. There has been no previous study on the effect of continuous intravenous infusion of epinephrine in patients with severe acute urticaria.
OBJECTIVE
This study investigated the efficacy and safety of continuous intravenous infusion of low-dose epinephrine in patients with severe acute urticaria who did not achieve a sufficient response to conventional treatments.
METHODS
We retrospectively reviewed the medical records of 74 patients with severe acute urticaria who were treated with continuous intravenous infusion of low-dose epinephrine between November 2008 and December 2016. One milligram (1 mL) of 1:1000 epinephrine was diluted in 1 L of saline to yield a concentration of 1 µg/mL. The solution was infused at 0.67 µg/min (40 mL/h). Vital signs were checked at 0, 30, 60, and 90 minutes after infusion of epinephrine. Epinephrine was discontinued after one symptom-free day.
RESULTS
Clinical symptoms initially resolved within 24.8 hours on average and symptoms were completely resolved within 73.4 hours on average. Twenty-four adverse events, including palpitation, chest discomfort, hand tremor, increased blood pressure, and elevated cardiac markers, were observed in 19 patients (25.7%). Most adverse events were mild and regressed spontaneously without further management. Four patients (5.4%) stopped the infusion due to adverse events, but all events regressed spontaneously after stopping epinephrine. Six weeks after completion of intravenous infusion of epinephrine, 68 patients (91.9%) were symptom-free and six patients required antihistamines.
CONCLUSION
This study suggests that continuous intravenous infusion of low-dose epinephrine is a safe and effective treatment in patients with severe acute urticaria who do not achieve a sufficient response to conventional treatments.