European Adder Antivenom
Specific immunoglobulin (antivenom) used in the management of snake bites by the **European Adder** (*Vipera berus*). > **Clinical Warning:** The value of antivenom decreases with time following the bite. Benefits to local swelling are limited to administration within 24 hours post-bite; however, benefits towards systemic signs, when present, continue even with administration >24 hours post-bite. **Clinical Pearl:** There are no published studies conclusively supporting improved recovery time in small animals, but it remains the definitive treatment for severe envenomation. This antivenom is unlikely to work for other snake bites, and specialist help should be urgently sought for such bites. Urgent provision in the UK may be possible via the **VPIS ToxBox** service.
Mechanism: Contains specific **immunoglobulins** (typically equine-derived F(ab')2 fragments) raised against *Vipera berus* venom. These antibodies directly bind to and neutralize the circulating venom toxins → preventing further tissue damage, coagulopathy, and systemic toxic effects.
Dosing by species
- Adder bite envenomation · 10 ml per animal slow i.v. (regardless of size). Consider giving 0.5 ml i.v. first and then wait 20 min to test for anaphylaxis. · IV · Single dose · Once · Administer slowly. Dose is per animal, not weight-dependent, as the venom load is independent of the victim's size.
- Adder bite envenomation · 10 ml per animal slow i.v. (regardless of size). Consider giving 0.5 ml i.v. first and then wait 20 min to test for anaphylaxis. · IV · Single dose · Once · Administer slowly. Dose is per animal, not weight-dependent.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- No specific contraindications available, but use with extreme caution in animals with known hypersensitivity to equine proteins.
Adverse effects
- Anaphylactic reactions (can be severe)
- Facial swelling (unrelated to the snake bite itself)
- Profound panting
- Unproductive cough
Monitoring
- Signs of anaphylaxis during and immediately after administration (panting, facial swelling, hypotension, collapse)
- Progression or resolution of local swelling
- Systemic signs of envenomation (coagulation parameters, cardiovascular status, renal function)
Overdose
No specific information available. The primary risk with large volumes of equine-derived serum is volume overload and an increased risk of hypersensitivity reactions (serum sickness).
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.