To evaluate the efficacy and safety of a new F(abʹ)₂ antivenom preparation in the treatment of Crotalinae envenomation in children.

We present a case series of children younger than 16 years who suffered Crotalinae envenomation and were treated with a new F(abʹ)₂ antivenom. Envenomated children treated with the new antivenom were assessed for efficacy of the product, defined as improvement of any hemotoxicity (hypofibrinogenemia, defined as fibrinogen <150 mg/dL, or thrombocytopenia, defined as platelets <150 000/mm³), and the cessation of the advancement of swelling. Safety was also evaluated by monitoring for adverse events. A secondary parameter assessed in these children was recurrent hemotoxicity after initial control of signs and symptoms with follow-up visits and laboratory testing on posttreatment days 5, 8, and 15.

Twenty-one children received the F(abʹ)₂ antivenom. Efficacy was achieved in all children receiving the product with initial control of swelling and improvement in those with hemotoxicity. No patients suffered anaphylaxis or any other serious adverse events from the F(abʹ)₂ treatment. There were no cases of recurrent hemotoxicity recorded in the study between time of initial control and postinfusion day 15.

In this series of children, the F(abʹ)₂ antivenom appeared to be both safe and effective in the treatment of hemotoxicity and local tissue toxicity (swelling) from Crotalinae envenomation.