Use of Snake Antivenom and Clinical Outcomes in Snake Envenomation: A Retrospective Study in a Tertiary Hospital in Penang, Malaysia

Backgrounds: Snake antivenom (SAV) is the definitive treatment for snake envenomation. But SAVs are specific, expensive and limited in supply. SAVs also come with risk of adverse reactions. Hence, this study was conducted to assess the use of SAV, adverse reactions to SAV and its clinical outcomes in snakebite patients. Methods: This was a retrospective study. Medical records of snakebite patients for the period from January 2014 to September 2017 were reviewed and study data was extracted. Clinical outcomes were measured by mortality rate in those receiving SAV. Results: Among 165 subjects, only 9 patients (5%) were treated with SAV after presenting with envenomation symptoms in which five cases with identified snakes were given monovalent SAV namely pit viper (two cases), king cobra, sea snake and cobra with one case each. Meanwhile, three cases of unidentified snake received polyvalent SAV and one case received pit viper SAV. Most of the patients (8/9, 88.9%) received SAV within 24 hours after snakebite. The average time gap to first administration was 7.23 hours. In patients receiving SAV, six out of 9 cases required two to four vials of SAV. All the patients receiving SAV did not encounter any adverse effects except a child who had pyrogenic reaction. All patients survived without significant morbidity at discharge. The total cost of SAV for the 9 patients was US$ 24,082.68. Conclusion: From this study, the incidence of snakebites requiring SAV was low. Low incidence of adverse effects and no mortality were observed in patients receiving SAV.