Snake Venom Antiserum (Polyvalent) is a sterile, purified, and concentrated preparation of equine immunoglobulins (IgG) obtained from the plasma of horses hyperimmunized against the venoms of the four most medically significant snakes in the Indian subcontinent: the Indian Cobra (Naja naja), Common Krait (Bungarus caeruleus), Russell's Viper (Daboia russelii), and Saw-scaled Viper (Echis carinatus). It is a life-saving biological product used for the passive immunization and neutralization of circulating venom toxins in cases of snakebite envenomation. It works by binding to and neutralizing venom antigens, preventing their toxic effects on tissues, blood, and the nervous system.
Adult: Initial dose: 10 vials (100 ml) is a common starting point for severe envenomation, but the dose is NOT FIXED. It is titrated based on the severity and progression of envenomation. Doses of 20-30 vials (200-300 ml) may be required for severe Russell's viper bites. The 10ml vial is one unit; multiple vials are reconstituted and pooled.
Note: 1. Perform skin sensitivity test (intradermal) as per manufacturer's instructions, but be prepared for anaphylaxis regardless of test result. 2. Have adrenaline (1:1000), antihistamines, and corticosteroids ready. 3. Reconstitute each lyophilized vial with provided Water for Injection. 4. Pool the required number of vial contents. 5. Administer slowly IV over 30-60 minutes, initially at a slower rate under close monitoring for first 10 minutes. 6. Intramuscular administration is NOT recommended for systemic envenomation due to delayed absorption. 7. Dilution in Normal Saline or 5% Dextrose (1:1 or 1:2) is common to reduce infusion reactions.
The antiserum contains specific F(ab')2 fragments or whole IgG antibodies directed against the toxic components (neurotoxins, hemotoxins, cytotoxins, myotoxins, coagulopathins) of the four snake venoms. These antibodies bind with high affinity to the venom antigens, forming immune complexes. This binding neutralizes the toxins by preventing their interaction with physiological targets (e.g., acetylcholine receptors, coagulation factors, platelets, muscle membranes). The formed complexes are then cleared by the reticuloendothelial system.
Pregnancy: Category C: Use if clearly needed. Snake envenomation poses a significant threat to both mother and fetus (placental hemorrhage, fetal distress). The benefits of treatment outweigh the risks. No teratogenic effects are known, but anaphylaxis can be catastrophic.
Driving: Not applicable. Patients are critically ill and hospitalized.
| Adrenaline (Epinephrine) | Used to treat anaphylaxis induced by the antiserum. It is a therapeutic interaction, not a contraindication. | Major (Therapeutic) |
| Antihistamines (e.g., Chlorpheniramine) | Pre-medication may reduce early allergic symptoms but does not prevent anaphylaxis. | Moderate |
| Corticosteroids (e.g., Hydrocortisone, Dexamethasone) | Pre-medication may reduce severity of serum sickness and allergic reactions. Often administered concurrently. | Moderate |
| ACE Inhibitors | May potentiate hypotensive episodes during an anaphylactic reaction. | Moderate |
Same composition (Snake Venom Antiserum (Polyvalent) (10ml)), different brands: