Antivenoms

Antivenoms are biologic products that neutralize venom toxins. They are produced by immunizing animals with venom and then harvesting and purifying the resulting antibodies, or by using monoclonal antibodies derived from cloned cells. The most common clinical antivenoms are polyclonal antisera raised in horses or sheep and purified for medical use; some newer formulations use antibody fragments such as Fab or F(ab')2 to reduce the risk of adverse reactions.

Production typically involves collecting venom from the target species, immunizing the animal with small, non-lethal doses, and boosting the immune response over time. Once sufficient antibody levels are present, serum is collected and processed to isolate immunoglobulins or fragments. Antivenoms can be monospecific, targeting a single species’ venom, or polyvalent, designed to neutralize venoms from multiple species that are relevant in a given region.

Mechanism of action: antibodies bind venom toxins, neutralizing their effects and preventing interaction with physiological targets. This can mitigate neurotoxic, cytotoxic, coagulopathic, or myotoxic effects depending on the venom. Efficacy depends on timely administration; antivenoms may not reverse damage already caused by irreversible injury and require supportive medical care.

Safety and regulation: antivenoms can provoke hypersensitivity reactions, including anaphylaxis or serum sickness. Modern products are highly purified, and some formulations use fragments to lessen risk. They are stored refrigerated and have limited shelf life. Availability, formulation, and dosing vary by region, and ongoing research aims to improve specificity, breadth of coverage, and reduce adverse events.