When and how should antivenom therapy be initiated or arranged for a patient with a venomous snake bite?

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 ¹.

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 ¹.

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., 2009; Freiermuth 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 ¹ (Lavonas et al., 2009).