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

Abstract

OBJECTIVETo 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. ANIMALS282 dogs with evidence of crotalid envenomation treated with antivenom at a single high-volume private emergency facility in southwestern Arizona from 2014 to 2018. PROCEDURESData 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. RESULTS271 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. CONCLUSIONS AND CLINICAL RELEVANCEGiven 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.

Neurologic and hematologic sequalae following a timber rattlesnake (Crotalus horridus) envenomation in a dachshund

“…The commercially available antivenom products available in the Western hemisphere are highly purified and are typically safe with low hypersensitivity rates ( Carotenuto et al, 2021 ; Bassett and Schaer, 2022 ). Because the patient had prolonged severe hypotension, the choice to place them on gastroprotectants and antibiotics was made.…”

Global parameter optimisation and sensitivity analysis of antivenom pharmacokinetics and pharmacodynamics

“…While we were unable to find experimental studies comparing the in vivo function of nanobody and scFv antivenoms with conventional scaffolds, there is evidence to support a tolerance of differently sized conventional antivenoms in envenomation treatment. Several studies have described the similar treatment of viper envenomation with Fab, F(ab')2, and IgG scaffolds, in both human and animal studies (Carotenuto et al, 2021;Chaves et al, 2003;Dart and McNally, 2001;Gerardo et al, 2021;León et al, 2001León et al, , 1997Mascarenas et al, 2020). One study also describes the effective treatment of an elapid venom with both IgG and F(ab')2 antivenoms (León et al, 1999).…”

“…Some studies report antivenom choice to have a significant impact on certain treatment outcome metrics (Boels et al, 2020;Bush et al, 2015;Ismail and Abd-Elsalam, 1998;Kurtović et al, 2021;Mascarenas et al, 2020;Morais et al, 1994;Resiere et al, 2020;Rivière et al, 1998Rivière et al, , 1997Wilson et al, 2022). Conversely, other studies report no impact (Carotenuto et al, 2021;Chaves et al, 2003;Dart and McNally, 2001;Gerardo et al, 2021;León et al, 2001León et al, , 1999León et al, , 1997. These studies assess different host species, venoms, antivenoms, doses, and treatment metrics, hindering a unified assessment of the impact of antivenom format.…”

Mechanical ventilation in snake envenomation of dogs and cats

“…Antivenom is a crucial part of treatment for any patient with clinical evidence of snake envenomation. Antivenom is produced by injecting venom or components into a host (most commonly horses) and extracting the newly formed IgG antibodies from the plasma ( 40 , 41 ). IgG antibodies bind to the active unbound venom antigen, forming masses of immune complexes that are readily phagocytized, inhibiting attachment to receptor sites ( 42 ).…”