VIEKVIN solution for injection – antivenom against nose-horned viper and adder venom after a snakebite

VIEKVIN is a solution for injection containing antibodies – antitoxic globulins in the form of F(ab)2 fragments – capable of neutralising the venom of European venomous snakes, the nose-horned viper (Vipera ammodytes) and the common adder (Vipera berus). The specific immunoglobulins are obtained from the plasma of healthy horses immunised with nose-horned viper venom.

The medicine is used to treat bites by venomous snakes of the genus Vipera. It is produced by the Torlak Institute in Belgrade and is administered only by a doctor or nurse in a healthcare facility. VIEKVIN is not effective against the venom of other snakes.

When is VIEKVIN used and how is it given after a snakebite?

Key facts about the medicine

What is VIEKVIN used for?

VIEKVIN is used to treat bites by venomous snakes of the genus Vipera – the nose-horned viper (Vipera ammodytes) and the common adder (Vipera berus).

• The antiserum is not effective against the venom of other snakes.
• It is not given routinely after every snakebite – before use the doctor assesses early clinical signs of envenomation (sharp pain and swelling at the bite site spreading rapidly, numbness around the bite) or signs of systemic poisoning (shock, spontaneous bleeding, clotting disorder, reduced urine output).
• Symptomatic hospital treatment is necessary even when the patient has received the antiserum.

How is it given and dosed?

The medicine is given by a doctor or nurse trained in administering this type of medicine. The dose is the same for adults and children:

• In patients with previous allergic reactions or allergic diseases, rapid desensitisation is attempted: 0.1 mL subcutaneously, after 15 minutes 0.25 mL subcutaneously, then – if there is no reaction – the rest of the dose intramuscularly.
• Injection close to the bite site is avoided because of impaired circulation and swelling.
• Even 24 hours after the bite, the antiserum may be useful if the clinical picture requires it.

Special patient groups

• Children: the therapeutic dose is the same as for adults (5 mL or 10 mL).
• People with allergies: asthma, eczema and previous exposure to horse proteins require a detailed history and special caution; after previous reactions to horse serum, an antitoxin from another animal species is given, and if not available, rapid desensitisation is attempted.
• Pregnant and breast-feeding women: there are no absolute contraindications, as the antiserum is used in life-threatening situations.

Contraindications – when the medicine must not be used

Allergy (hypersensitivity) to horse proteins or to the excipients is a relative contraindication, because the antiserum is vital in severe snake venom poisoning. People who had local or general hypersensitivity reactions to horse antitoxin before should receive an antitoxin from another animal species or undergo rapid desensitisation.

Warnings and precautions

• Before use, a detailed history of previous hypersensitivity reactions, especially to proteins of equine origin, and of allergic diseases (asthma, eczema) is essential.
• Appropriate medical treatment must be available during administration to manage anaphylactic shock promptly.
• First aid in the field: the wound must not be cut and the venom must not be sucked out – this is useless and often dangerous. Proper immobilisation of the bitten limb is recommended; paracetamol may be used for pain. During transport, lay the person on their side, keep the airway open and bring them to a healthcare facility as soon as possible.
• In hospital, white blood cell differential, ECG, markers of metabolic acidosis and creatine kinase are monitored.

Interactions with other medicines, food and drink

There is no evidence of interactions with other medicines. The antiserum must not be mixed with other medicines or sera, nor in the same syringe. Tell the doctor about all medicines you or your child are taking.

Pregnancy and breast-feeding

There are no absolute contraindications in pregnancy and breast-feeding, as the antiserum is used in life-threatening situations. The doctor decides on its use.

Driving and using machines

There is no information indicating that the medicine affects the ability to drive or use machines; the doctor decides when normal activities can be resumed after a snakebite.

Possible side effects

• Anaphylactic shock – may occur during or immediately after administration: drop in blood pressure, difficulty breathing, hives and shock.
• Serum sickness – occurs 4–7 days (sometimes up to 3 weeks) after administration: fever, pain and swelling of some joints and lymph nodes, vomiting, diarrhoea, narrowing of the airways and hives.
• Hypersensitivity reactions – muscle pain, nausea, hot flushes, redness and other local reactions; administration is then stopped immediately.

Anaphylaxis is treated urgently (adrenaline, antihistamine, corticosteroid and other measures according to symptoms), and serum sickness with antihistamines, antipyretics/NSAIDs and, for more severe symptoms, corticosteroids – as decided by the doctor.

Overdose, missed dose and stopping treatment

• Overdose: the incidence of anaphylaxis and serum sickness depends on the amount of horse protein given.
• Missed or delayed administration: if more than 4 hours have passed since the bite, the dose is 10 mL (2 vials) intramuscularly; even after 24 hours administration may be useful if the clinical picture requires it.
• Stopping: not applicable – the medicine is given in life-threatening situations under medical supervision.

Related information

The medicine is used only in healthcare facilities as emergency treatment after a venomous snakebite. For any questions about first aid and further treatment, contact the emergency doctor or your family doctor.

Composition, pack and manufacturer

• Active substance: snake venom antiserum (equine); 1 mL neutralises at least 100 LD50 of nose-horned viper venom and 50 LD50 of adder venom.
• Excipients: phenol 2.5 mg; sodium hydroxide q.s.; sodium chloride 9.0 mg; water for injections to 1.0 mL. Essentially sodium-free (less than 23 mg per dose).
• Pack: colourless type I glass vial (5 mL) with rubber stopper and aluminium cap, a sterile 5 mL syringe and two sterile needles 0.8 x 40 mm.
• Marketing authorisation holder and manufacturer: Institute of Virology, Vaccines and Sera “Torlak”, Vojvode Stepe 458, Belgrade.

Storage

• Store in a refrigerator (2–8 °C) in the original package. Do not freeze – frozen medicine must not be used.
• Once the vial is opened, the medicine must be used immediately. Shelf life of the unopened medicine is 3 years.
• Keep out of the reach of children; dispose of unused medicine in accordance with regulations.

Frequently asked questions

Is VIEKVIN given after every snakebite?

No. According to the leaflet, the antiserum is not given routinely after every bite – the doctor uses it when there are signs of envenomation, such as rapidly spreading pain and swelling, numbness or signs of systemic poisoning.

Does VIEKVIN work against the venom of all snakes?

No. It is effective only against the venom of snakes of the genus Vipera – the nose-horned viper and the common adder – and does not work against the venom of other snakes.

What should be done immediately after a snakebite?

The person should be taken to the nearest healthcare facility as soon as possible, the bitten limb properly immobilised and the person laid on their side during transport. The wound must not be cut and the venom must not be sucked out; paracetamol may be given for pain.

What side effects are possible after administration?

Anaphylactic shock may occur during or immediately after administration, and serum sickness 4–7 days later (sometimes up to 3 weeks) – fever, pain and swelling of joints and lymph nodes, rash, vomiting and diarrhoea.

Sources

• ALIMS – VIEKVIN solution for injection – document with information for healthcare professionals (published as SmPC, Serbian)
• ALIMS – Package leaflet, VIEKVIN solution for injection (PIL, Serbian)

Sources checked on: 25 October 2026.