Snake Envenomation
Adesola Odunayo, DVM, MS, DACVECC, University of Florida
ANTIVENOM RECOMMENDATIONS
Clinicians should start with one vial of antivenom per patient; however, patients with a lower body weight may require more antivenom,1-5 as smaller patients tend to receive a larger amount of venom per kg of body weight when bitten (eg, a Chihuahua vs a Great Dane injected with the same amount of venom).5
If the antivenom is lyophilized, one vial should be reconstituted with crystalloid fluids (100-250 mL).5
Antivenom should be administered intravenously over 1 to 2 hours.2,3
Patients should be monitored for signs of anaphylactoid/anaphylactic reactions.
Diphenhydramine may be considered if anaphylaxis or a mild anaphylactoid reaction to the antivenom is suspected, whereas epinephrine and intravenous fluids should be administered for severe anaphylaxis/anaphylactoid reactions.2 Administration of antivenom should be stopped in both instances.4 However, if the reaction is not severe, administration of antivenom should be slowly resumed after approximately 20 to 60 minutes.4 Additional support in patients with hypotension (eg, vasopressors) and/or respiratory signs (eg, mechanical ventilation) may be required.1
*Coral snakes and pit vipers (eg, rattlesnakes, copperheads, water moccasins, cottonmouths) are among the venomous snakes found in the United States.2,4
ALP = alkaline phosphatase, ALT = alanine transaminase, AST = aspartate aminotransferase, GGT = gamma-glutamyl transferase, PCV = packed cell volume, TS = total solids