European Adder Antivenom
Equine-derived F(ab')2-antivenin (Vipera berus)
Also known as: European Adder Antivenom · Vipera berus antivenom · Adder antivenin · Viper antivenom
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| 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 | 🌍 EU |
- Adder bite envenomation: Administer slowly. Dose is per animal, not weight-dependent, as the venom load is independent of the victim's size.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| 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 | 🌍 EU |
- Adder bite envenomation: 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.
Overview
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 of action
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.
Safety & warnings
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
Precautions
Anaphylaxis Risk: Equine-derived antivenoms carry a significant risk of hypersensitivity/anaphylaxis. It is strongly recommended to administer a small test dose (e.g., 0.5 ml IV) and observe for 20 minutes before administering the full dose.
- Supply & Import: In the UK, current approved suppliers can be found on the VMD website. A special dispensation from the VMD can enable supply, purchase, and use prior to STC approval in urgent cases.
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)
Pharmacokinetics
Half-life
Absorption
Administered intravenously for immediate systemic availability.
Distribution
Distributes through extracellular fluid to bind circulating venom.
Metabolism
Degraded by the reticuloendothelial system like other immunoglobulins.
Elimination
Cleared via normal protein degradation pathways.
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).
Available products
Formulations
- Injectable: 10 ml vial for injection (100 mg/ml)
Veterinary
- 10 ml vial for injection (100 mg/ml)
Regulatory status
Availability and specific approvals vary by member state.
Special dispensation from the VMD can enable supply, purchase, and use prior to STC approval in urgent cases. Urgent provision may also be possible via the VPIS ToxBox service.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store according to manufacturer instructions, typically refrigerated (2°C to 8°C). Do not freeze.
Client information
If your pet is bitten by a snake, keep them as calm and still as possible and seek emergency veterinary care immediately. Do not attempt to suck out the venom or apply a tourniquet.
Antivenom is the most effective treatment for severe bites, but it carries a risk of allergic reactions. Your vet will monitor your pet closely during administration. Recovery can take several days, and strict rest is essential.
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.