METHODOLOGY/PRINCIPLE FINDINGS: The D. siamensis monovalent antivenom displayed extensive recognition and binding to proteins found in D. siamensis venom, irrespective of the geographical origin of those venoms. Similar immunological characteristics were observed with the Hemato Polyvalent antivenom, which also uses D. siamensis venom as an immunogen, but binding levels were dramatically reduced when using comparator monovalent antivenoms manufactured against different snake species. A similar pattern was observed when investigating neutralization of coagulopathy, with the procoagulant action of all four geographical venom variants neutralized by both the D. siamensis monovalent and the Hemato Polyvalent antivenoms, while the comparator monovalent antivenoms were ineffective. These in vitro findings translated into therapeutic efficacy in vivo, as the D. siamensis monovalent antivenom was found to effectively protect against the lethal effects of all four geographical venom variants preclinically. Assessments of in vivo nephrotoxicity revealed that D. siamensis venom (700 μg/kg) significantly increased plasma creatinine and blood urea nitrogen levels in anaesthetised rats. The intravenous administration of D. siamensis monovalent antivenom at three times higher than the recommended scaled therapeutic dose, prior to and 1 h after the injection of venom, resulted in reduced levels of markers of nephrotoxicity and prevented renal morphological changes, although lower doses had no therapeutic effect.
CONCLUSIONS/SIGNIFICANCE: This study highlights the potential broad geographical utility of the Thai D. siamensis monovalent antivenom for treating envenomings by the Eastern Russell's viper. However, only the early delivery of high antivenom doses appears to be capable of preventing venom-induced nephrotoxicity.
METHODS: This was a 4-year cross-sectional study of snakebite patients from January 2013 to December 2016 in Hospital Sultanah Nur Zahirah (HSNZ), Terengganu. Data was extracted from the Pharmacy Record on the usage of antivenom and patients of snakebites treated with antivenom were identified. Data of patients were then obtained from the electronic medical records.' Demographic details, clinical features and characteristics of antivenom reactions of patients were recorded in standardized data collection forms and analyzed using chi-square or Mann- Whitney U tests.
RESULTS: Of the 44 patients who received antivenom, 24 (54.5%) developed hypersensitivity reaction. All patients developed reaction early. No patient developed delayed (serum-sickness) reaction. Of the 24 patients, 14 (58.3%) had moderate to severe hypersensitivity reaction and 9 (37.5%) patients had mild reactions. Only one (4.2%) patient presented with bradycardia.
CONCLUSION: The prevalence of early hypersensitivity reaction to snake antivenom in HSNZ was relatively high. Healthcare providers should be aware of the appropriate method of preparing and administering antivenom, and the management for acute hypersensitivity reactions. This will optimize the management of snakebite and ensure patient safety.