Types of Antivenom Available in India
India primarily produces and uses a polyvalent (polyspecific) antivenom that targets the "Big Four" venomous snakes: the spectacled cobra (Naja naja), common krait (Bungarus caeruleus), Russell's viper (Daboia russelii), and saw-scaled viper (Echis carinatus). 1, 2
Primary Antivenom Type
Indian Polyvalent Antivenom
- This is a single formulation containing antibodies against all four major venomous species, manufactured using equine (horse) serum through protocols that have remained essentially unchanged for over a century 1, 2
- The antivenom is produced by immunizing horses with venoms sourced mainly from Chennai in the southeastern state of Tamil Nadu 3
- Standard initial dosing is 10 vials administered intravenously after appropriate hypersensitivity testing 4, 5
Coverage and Limitations
The "Big Four" Coverage
The polyvalent antivenom specifically targets:
- Spectacled cobra (Naja naja) - neurotoxic venom 1, 2
- Common krait (Bungarus caeruleus) - neurotoxic venom causing paralysis and respiratory failure 5, 1
- Russell's viper (Daboia russelii) - hemotoxic and cytotoxic effects 3
- Saw-scaled viper (Echis carinatus) - hemotoxic effects 1, 2
Critical Deficiencies in Current Antivenom
The marketed Indian polyvalent antivenom exhibits disturbing deficiencies in neutralizing venoms from medically important snakes beyond the "Big Four," including other cobra species (Naja kaouthia), krait species (Bungarus sindanus, Bungarus fasciatus), and regional variants of the saw-scaled viper (Echis carinatus sochureki) 2
Geographic variability creates additional problems: The same antivenom shows poor efficacy against northern Indian populations of Bungarus caeruleus (one of the "Big Four") because venoms are sourced only from southern India 2, 3
Cross-Reactivity Considerations
- Limited evidence suggests possible cross-neutralizing activity against some non-targeted species, such as the shore pit viper (Trimeresurus purpureomaculatus), though this requires further validation 6
- Different manufacturers (such as Premium Serums and Haffkine) produce variations of the polyvalent antivenom, but Premium Serums antivenom has failed to neutralize bites from several neglected species and even some "Big Four" populations 2
Clinical Implications
India does NOT produce monospecific (single-species) antivenoms or region-specific formulations, despite documented inter- and intraspecific venom variations across the subcontinent 2, 3
This represents a major gap in snakebite management, as India experiences the highest annual snakebite mortality (46,000-58,000 deaths) and disability rates (140,000) globally 1, 2