Safety profile of antivenom in a cohort of patients envenomed by Deinagkistrodon acutus in Hangzhou, Zhejiang Province, Southeast China.

Introduction: Antivenom treatment is the specific treatment for Deinagkistrodon acutus envenomation. However, safety concerns regarding the use of antivenom in this population have been reported only infrequently in the literature. We aimed to determine the incidence of anaphylactic reactions and serum sickness following antivenom administration in a cohort of patients envenomed by Deinagkistrodon acutus.

Methods: We retrospectively reviewed the medical records of patients admitted to the Hangzhou TCM Hospital between January 2018 and December 2022 with bites from Deinagkistrodon acutus. The information collected included patient demographics, clinical information, laboratory findings, details of antivenom use, use of premedications, and details of anaphylactic reactions and serum sickness.

Results: A total of 157 patients with bites from Deinagkistrodon acutus were treated with antivenom (median dose four vials) and were included in the study. All treated patients received premedications (dexamethasone and antihistamines). Adverse reactions were noted in 18 patients (11.5%). Ten of these individuals (6.4%) suffered anaphylactic reactions within the first 24 h following antivenom administration, categorized as mild (n = 5), moderate (n = 4), or severe (n = 1). Symptoms included rash, urticaria, diaphoresis, nausea, dyspnoea, wheezing, anaphylactic shock, loss of consciousness, and angioedema. Serum sickness occurred in eight patients (5.1%), manifesting primarily as urticaria or erythematous rash, fever, myalgia, arthralgia, malaise, and gastrointestinal symptoms.

Discussion: This study provided data on adverse reactions associated with antivenom administration in patients admitted with bites from Deinagkistrodon acutus admitted to a regional referral centre specializing in the management of patients with severe or complex health conditions in Zhejiang Province, China. Our results indicate a relatively low incidence of severe adverse reactions. Nevertheless, clinicians must administer appropriate snake antivenom and maintain vigilance during antivenom administration and post-treatment follow-up.

Conclusions: Antivenom therapy was efficacious in treating Deinagkistrodon acutus envenomation. Approximately one in every eight patients developed anaphylactic reactions or serum sickness, although anaphylactic shock was uncommon (0.6%).