Retrospective comparison of three antivenoms for the treatment of dogs with crotalid envenomation.

Abstract

To retrospectively compare clinical outcomes associated with 3 commercially available antivenom products (2 F[ab']2 products and 1 IgG product) in dogs with crotalid envenomation. 282 dogs with evidence of crotalid envenomation treated with antivenom at a single high-volume private emergency facility in southwestern Arizona from 2014 to 2018. Data were collected on all dogs regarding signalment, coagulation test results, snakebite characteristics, type and number of units of antivenom received (1 of 3 products), survival to hospital discharge (yes or no), and complications following discharge. Survival rates and other variables were compared among antivenoms by means of bivariable analyses. 271 of 282 (96.1%) dogs survived to discharge; 11 (3.9%) were euthanized or died in the hospital. No significant difference in survival rates was found among the 3 antivenom products. Infusion reaction rates were higher for the IgG product than for each F(ab')2 product. A higher percentage of dogs treated with the IgG product (vs either F[ab']2 product) received only 1 unit of antivenom. Variables associated with a lower probability of survival included older age and lower body weight, thoracic (vs other) location of snakebites, and presence of an antivenom infusion reaction. Given that survival rates were high for all 3 antivenom products, clinicians may consider other factors when selecting an antivenom, such as preference for a fractionated versus whole immunoglobulin product, risk of infusion reaction, cost, shelf life, availability, ease of use and administration, species of crotalids used for antivenom production, approval by federal regulatory bodies, and clinical preference.