The critical time period for administering antivenom: golden hours and missed opportunities.

Abstract

Introduction: Antivenom is widely accepted as an effective treatment for snake envenomation. This is despite very limited evidence supporting clinical effectiveness for major envenomation syndromes, and is mainly based on pre-clinical studies and observational studies without control groups.

Effectiveness of early antivenom: Although antivenom exhibits efficacy by binding to snake toxins and preventing toxic injury in animals if pre-mixed with venom, this efficacy does not always translate to clinical effectiveness. There are many irreversible venom mediated effects that antivenom cannot neutralise or reverse, such as pre-synaptic neurotoxicity and myotoxicity. Fortunately, early antivenom appears to prevent some of these.

Practicalities of administering antivenom early: With good evidence that early antivenom prevents some envenomation syndromes, the time between bite and antivenom administration must be reduced. This requires improving the initial assessment of snakebite patients, and improving early decision making based on clinical effects.

Conclusion: Until there are improved, simplified, easy to use, rapid and inexpensive tests, whether available in the laboratory or preferably at the bedside that identify systemic envenomation, the key to early antivenom administration is early assessment and decision making based on systemic symptoms, including nausea, vomiting, headache and abdominal pain.