Antivenom therapy should be initiated promptly in patients with signs of systemic envenomation or progressive local tissue damage following a venomous snake bite. This includes symptoms such as coagulopathy, neurotoxicity, hypotension, or extensive swelling and necrosis at the bite site. Early administration is critical to neutralize circulating venom and prevent further complications NICE CG134.
In practice, antivenom should be arranged as soon as clinical assessment confirms envenomation severity, ideally in a hospital setting equipped for monitoring and managing potential allergic reactions. The antivenom is administered intravenously under close observation for anaphylaxis or serum sickness, with resuscitation facilities immediately available NICE CG134.
Recent evidence from North American pit viper envenomation supports the effectiveness of Fab antivenom in severe cases, showing improved outcomes and reduced opioid use for pain management. This underscores the importance of timely antivenom therapy to mitigate both systemic toxicity and pain Lavonas et al. 2009Freiermuth et al. 2019.
Therefore, the decision to initiate antivenom should be based on clinical signs of envenomation severity rather than the presence of a bite alone, with arrangements made urgently for administration in an appropriate clinical environment. Supportive care and monitoring remain essential adjuncts to antivenom therapy NICE CG134 Lavonas et al. 2009.
Key References
- CG134 - Anaphylaxis: assessment and referral after emergency treatment
- NG40 - Major trauma: service delivery
- NG228 - Subarachnoid haemorrhage caused by a ruptured aneurysm: diagnosis and management
- (Lavonas et al., 2009): Crotaline Fab antivenom appears to be effective in cases of severe North American pit viper envenomation: an integrative review.
- (Freiermuth et al., 2019): Antivenom Treatment Is Associated with Fewer Patients using Opioids after Copperhead Envenomation.