Use of both Fab and F(ab') fragment antivenom in a pediatric patient for treatment of a North American Crotalidae envenomation.

Crotalidae envenomation has been managed successfully in emergency departments across the world with antivenom. Over the years, antivenom has evolved and newer agents have been studied with the possibility of eliminating maintenance antivenom therapy. Here we report a patient who had worsening platelet and fibrinogen concentrations, as well as complaints of swelling and pain at the site of a rattlesnake envenomation following an initial dose of F(ab')AV (Crotalidae immune F(ab') (equine) [ANAVIP®]) Crotalidae antivenom. The patient was subsequently transferred to a tertiary children's hospital for a higher level of care and received FabAV (Crotalidae polyvalent immune Fab (ovine) [CroFab®]) Crotalidae antivenom. The details of this patient's treatment course highlight the possibility that patients who receive F(ab')AV, may require additional antivenom treatment. Furthermore, it appears that based on our single patient experience, giving FabAV after F(ab')AV is safe and effective.