North American Coral Snake Antivenin
**North American Coral Snake Antivenin** is a life-saving antidote specifically formulated to treat envenomation from the **Eastern coral snake** (*Micrurus fulvius fulvius*) and the **Texas coral snake** (*Micrurus fulvius tenere*). > **Important Clinical Pearl:** This antivenin will **NOT** neutralize venom from the Sonoran/Arizona coral snake (*Micruroides euryxanthus*) or the Brazilian giant coral snake (*Micrurus frontalis*). Unlike pit viper venom, which causes severe local tissue necrosis and coagulopathy, coral snake venom is primarily **neurotoxic**. Clinical signs of envenomation (such as ascending flaccid paralysis, loss of gag reflex, and respiratory failure) may be delayed by up to 12-24 hours. Therefore, any animal suspected of a coral snake bite should be hospitalized for close observation for at least 24-48 hours.
Mechanism: Antivenins provide **passive immunity** by supplying pre-formed neutralizing antibodies (globulins) derived from horses hyperimmunized with coral snake venom. * **Mechanism:** The antibodies directly bind to the complex venom proteins (specifically **alpha-neurotoxins**) in the patient's bloodstream. * **Pathway:** Venom-antibody binding → prevents neurotoxins from attaching to **nicotinic acetylcholine receptors** at the neuromuscular junction → halts the progression of flaccid paralysis and respiratory depression. * Each vial neutralizes approximately 2 mg of *M. fulvius fulvius* venom.
Dosing by species
- Coral Snake envenomation · 1-2 vials of antivenin. Initially give one vial, by diluting to 100-250 mL of crystalloid fluids and initially administering by slow IV . In smaller patients, adjust infusion volume to prevent fluid overload. Give additional vials as indicated by the progression of the syndrome. · slow IV · Initially, then as indicated · Dose necessary is calculated relative to the amount of venom injected and the body mass of patient. Smaller patients may require higher doses.
- Coral Snake envenomation (systemic effects) · Administer 1-2 vials slowly IV diluted in 250-500 mL saline or lactated Ringer's. · IV · Once, use only if necessary · Use only if necessary to treat systemic effects, otherwise avoid use. Administer antihistamines; corticosteroids are contraindicated. May be used with Crotilidae antivenin.
- Coral Snake envenomation · 1-2 vials initially, and more in 4-6 hours if necessary · IV · initially, and more in 4-6 hours if necessary · Therapy is best started within 4 hours after envenomation. Supportive care includes broad-spectrum antibiotics, fluid therapy and mechanical ventilation if necessary. Corticosteroids are not recommended.
- Coral Snake envenomation · 1-2 vials of antivenin. Initially give one vial, by diluting to 100-250 mL of crystalloid fluids and initially administering by slow IV . In smaller patients, adjust infusion volume to prevent fluid overload. Give additional vials as indicated by the progression of the syndrome. · slow IV · Initially, then as indicated · Dose necessary is calculated relative to the amount of venom injected and the body mass of patient. Smaller patients may require higher doses (as venom amount/kg body weight is higher).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Envenomation by Sonoran or Arizona Coral Snake (Micruroides euryxanthus)
Adverse effects
- Hypersensitivity reactions
- Anaphylaxis (incidence <2%)
- Anaphylactoid reactions
- Serum sickness
- Erythema and wheal formation (at injection site during sensitivity testing)
Drug interactions
- Analgesics / Sedatives · May mask the clinical signs associated with the venom; use initially with caution.
- Antihistamines · Theoretical potentiation of venom, though undocumented. Diphenhydramine is routinely used by clinicians for pretreatment.
- Beta-blockers · May mask the early signs associated with anaphylaxis.
- Corticosteroids · Contraindicated for the treatment of snakebite envenomation itself, but may be useful to treat secondary anaphylaxis.
Monitoring
- Signs associated with an allergic response to the antivenin (anaphylaxis, anaphylactoid-reactions, serum sickness)
- Cardiorespiratory monitoring
- Mechanical ventilation parameters (if necessary)
- Pulse oximetry
Overdose
Specific overdosage information is not provided, but in smaller patients, care must be taken to adjust the infusion volume of the crystalloid diluent to prevent **fluid overload**.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.