Nerve‑gas antidotes - ED management (UK)
Nerve agents (sarin, VX, Novichok and other organophosphorus compounds) produce an acute cholinergic toxidrome by irreversibly inhibiting acetylcholinesterase (AChE).
Emergency department management focuses on staff safety and decontamination, rapid reversal of life‑threatening muscarinic effects with atropine, reactivation of AChE with an oxime (pralidoxime), seizure control and coordinated use of national antidote stocks and specialist advice.
UK practice follows the CBRN clinical management handbook and UKHSA incident guidance; contact the National Poisons Information Service (NPIS) early for clinical and logistics support (CBRN handbook; UKHSA; RCEM/NPIS).
Clinical features and antidotal rationale
- Toxidrome:
- Muscarinic excess: bronchorrhoea, bronchospasm, bradycardia, miosis, vomiting.
- Nicotinic effects: muscle fasciculations, weakness, paralysis including respiratory muscles.
- Central effects: confusion, seizures, coma.
- Antidotal strategy:
- Atropine: competitive muscarinic antagonist - reverses bronchorrhoea, bronchospasm, bradycardia and hypotension; does not restore AChE or reliably reverse nicotinic neuromuscular blockade.
- Oximes (pralidoxime, 2‑PAM Cl): chemically reactivate phosphorylated AChE and are required to reverse nicotinic neuromuscular effects; efficacy declines after enzyme “aging”, so early administration is preferable.
Immediate priorities (first actions)
1. Staff safety and decontamination