Red Flags
- Systemic envenomation (neurotoxic paralysis, ptosis, dysphagia, respiratory distress; haemotoxic bleeding; rhabdomyolysis; AKI) — emergency ASV; intubation if respiratory failure; ICU[1]
- Anaphylactic reaction to ASV (urticaria, hypotension, bronchospasm) — adrenaline 0.5 mg IM; pause and recommence ASV at slower rate after stabilisation[1]
- Krait bite (often nocturnal, painless local site, progressive paralysis 6–12 h post-bite) — high suspicion even without local signs; do NOT use atropine-neostigmine challenge in confirmed krait[1]
- Compartment syndrome from severe local swelling (cobra, Russell's viper) — measure compartment pressures; surgical decompression if intra-compartment pressure >40 mmHg or clinical features[1]
First-line treatment
Interventions
- First aid — reassurance, immobilisation, transport[1]Reassure; immobilise limb with splint; remove tight clothing/jewellery; transport to ASV-equipped facility immediately. Avoid tourniquets, incisions, suction, ice, traditional remedies — all cause harm and delay
- Hospital initial assessment[1]ABCDE; secure airway if respiratory compromise; IV access ×2; bloods; 20WBCT; mark progression of swelling with skin marker; serial neurological assessment; observe minimum 24 h before discharge if asymptomatic
- Polyvalent ASV indications[1]Systemic envenomation (incoagulable 20WBCT, neurotoxicity, rhabdomyolysis, AKI, haemodynamic instability) OR severe progressive local envenomation. Initial dose 10 vials in 100 mL normal saline IV over 30–60 min; repeat 10 vials every 6 h until 20WBCT normalises and neurology improves
- Pre-medication and reaction management[1]Adrenaline 0.25 mg SC or 1:1000 IM 5 min before ASV (national programme practice; some protocols selective); IV antihistamine and hydrocortisone; have full anaphylaxis kit ready; if reaction occurs, pause ASV, treat anaphylaxis, restart at slower rate
- Atropine-neostigmine for cobra envenomation[1]Indicated for cobra envenomation (post-synaptic neurotoxicity); atropine 0.6 mg IV + neostigmine 1.5 mg IV; reassess at 30 min; repeat if response. AVOID in krait envenomation (presynaptic neurotoxicity does not respond)
- Supportive care for haemotoxic envenomation[1]Fluid resuscitation; blood products only after ASV given (giving FFP/platelets without ASV is futile and risks transfusion reaction); haemodialysis for AKI; avoid NSAIDs and other nephrotoxins
- Tetanus prophylaxis and wound care[1]Tetanus toxoid booster if last dose >5 years; tetanus immunoglobulin if not fully immunised; clean wound; do not debride routinely; antibiotic only if cellulitis or bite contamination evident
First-line drug therapy
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Indian Polyvalent Anti-Snake Venom (ASV)[1] | Equine F(ab')2 / IgG anti-venom | 10 vials reconstituted in 100 mL 0.9% saline IV over 30–60 min; repeat 10 vials every 6 h until 20WBCT coagulable and neurology improving (max ~30 vials) | Same dose as adults — venom dose is fixed, not weight-based | Covers four species (Russell's viper, cobra, krait, saw-scaled viper) in Indian polyvalent preparation; check expiry; reconstitute correctly; pre-medication and reaction monitoring |
| Adrenaline (anaphylaxis prophylaxis / treatment)[1] | Sympathomimetic | Pre-ASV: 0.25 mg SC or 1:1000 IM 5 min before ASV. Treatment of anaphylaxis: 0.5 mg IM repeated every 5 min as needed | 10 µg/kg IM (max 0.5 mg) | Subcutaneous pre-medication per Indian programme; full anaphylaxis kit and IV access at all times during ASV administration |
| Atropine + neostigmine (cobra envenomation)[1] | Anticholinergic + acetylcholinesterase inhibitor | Atropine 0.6 mg IV + neostigmine 1.5 mg IV; assess at 30 min; repeat as response | Atropine 50 µg/kg + neostigmine 0.04 mg/kg IV | Cobra envenomation neuroparalysis (post-synaptic); not effective in krait; combines with ASV; adequate atropinisation prevents bradycardia from neostigmine |
| Hydrocortisone + chlorphenamine (reaction)[1] | Glucocorticoid + antihistamine | Hydrocortisone 100 mg IV; chlorphenamine 10 mg IV | Hydrocortisone 4 mg/kg IV; chlorphenamine 0.2 mg/kg IV | Adjunct to adrenaline in delayed reactions; not substitute for adrenaline in anaphylaxis; serum sickness 7–10 days after ASV warrants oral steroid |
Indian Polyvalent Anti-Snake Venom (ASV)[1]
Equine F(ab')2 / IgG anti-venom
- Adult
- 10 vials reconstituted in 100 mL 0.9% saline IV over 30–60 min; repeat 10 vials every 6 h until 20WBCT coagulable and neurology improving (max ~30 vials)
- Paediatric
- Same dose as adults — venom dose is fixed, not weight-based
Covers four species (Russell's viper, cobra, krait, saw-scaled viper) in Indian polyvalent preparation; check expiry; reconstitute correctly; pre-medication and reaction monitoring
Adrenaline (anaphylaxis prophylaxis / treatment)[1]
Sympathomimetic
- Adult
- Pre-ASV: 0.25 mg SC or 1:1000 IM 5 min before ASV. Treatment of anaphylaxis: 0.5 mg IM repeated every 5 min as needed
- Paediatric
- 10 µg/kg IM (max 0.5 mg)
Subcutaneous pre-medication per Indian programme; full anaphylaxis kit and IV access at all times during ASV administration
Atropine + neostigmine (cobra envenomation)[1]
Anticholinergic + acetylcholinesterase inhibitor
- Adult
- Atropine 0.6 mg IV + neostigmine 1.5 mg IV; assess at 30 min; repeat as response
- Paediatric
- Atropine 50 µg/kg + neostigmine 0.04 mg/kg IV
Cobra envenomation neuroparalysis (post-synaptic); not effective in krait; combines with ASV; adequate atropinisation prevents bradycardia from neostigmine
Hydrocortisone + chlorphenamine (reaction)[1]
Glucocorticoid + antihistamine
- Adult
- Hydrocortisone 100 mg IV; chlorphenamine 10 mg IV
- Paediatric
- Hydrocortisone 4 mg/kg IV; chlorphenamine 0.2 mg/kg IV
Adjunct to adrenaline in delayed reactions; not substitute for adrenaline in anaphylaxis; serum sickness 7–10 days after ASV warrants oral steroid
Safety-net
- Avoid tourniquets, incisions, suction, ice, and traditional remedies — they cause harm and delay reaching definitive treatment[1]
- Most bites are without envenomation ('dry bites') — observation for 24 h is essential as venom effects can be delayed (especially krait bites)[1]
- After discharge, watch for delayed bleeding, weakness recurring, dark urine, or decreased urine — return immediately for re-evaluation[1]
Referral criteria
- Suspected systemic envenomationEmergency department with ASV; ICU on respiratory or haemodynamic compromise[1]
- Refractory neurological deficit despite ASV and atropine-neostigmineTertiary toxicology / critical care for prolonged ventilation; consider repeat ASV[1]
- AKI requiring dialysisNephrology and ICU[1]
- Compartment syndrome of bitten limbOrthopaedics / vascular for fasciotomy after compartment pressure measurement[1]
Clinical summary
First aid, recognition of systemic envenomation, anti-snake venom administration, and supportive care for snakebite in adults and children.