Safety and Efficacy of Crotalidae Polyvalent Immune Fab in Pediatric Crotaline Envenomations

Abstract

In this pediatric series, CroFab appears safe and effective, despite occasional resistant thrombocytopenia.

Management of Tissue Loss After Agkistrodon Snakebite: Appropriate Use of Crotalidae-Fab Antivenin

“…Despite the low risk of severe morbidity and mortality, many health centers around the United States continue to treat copperhead and cottonmouth envenomations using CroFab. The use of CroFab may be largely attributed to the relatively low level of serious complications associated with the treatment ( Pizon et al, 2007 ). Nevertheless, given the high cost of the treatment and the low level of serious complications observed in Agkistrodon bites, treatment should be reserved for only the most severe envenomations ( Walker & Morrison, 2011 ;White & Weber, 1991 ).…”

“…However, common and sometimes severe side effects associated with equine antivenom lead to the development of Crotalidae Polyvalent Immune Fab (Ovine) ( Juckett & Hancox, 2002 ). In 2000, the U.S. Food and Drug Administration approved CroFab for the "treatment of minimal and moderate North American Crotalidae envenomation" and has since become the standard pit viper antivenom in the United States ( Cannon, Anne-Michelle, & Kashani, 2007 ;Pizon, Riley, LoVecchio, & Gill, 2007 ). Several species of pit vipers are indigenous to the southwest Missouri area including the copperhead ( Agkistrodon contortrix ), cottonmouth ( Agkistrodon piscivorus ), timber rattlesnake ( Crotalus sp.…”

Crotalidae Polyvalent Immune Fab for the Treatment of Pediatric Crotaline Envenomation

“…The elimination half-life of FabAV is considerably shorter than that of the crotaline venom components, which may necessitate repeat dosing to prevent or treat recurrence of toxicity. 21,22,24,25 …”

“…The final preparation is standardized to contain less than 1% of the Fc fragments to minimize the incidence of hypersensitivity reactions. 21,22 Mechanism of Action After intravenous administration, FabAV binds and neutralizes crotaline venom components that have been absorbed into the intravascular space, ameliorating systemic toxicity. The Fab-venom complex is then eliminated in the urine.…”

“…Pooled serum is collected from sheep inoculated with venom from 4 different North American crotaline snakes: Eastern Diamondback Rattlesnake (Crotalus adamenteus), Western Diamondback Rattlesnake (Crotalus atrox), Mojave Rattlesnake (Crotalus scutulatus), and the Cottonmouth or Water Moccasin (Agkistrodon piscivorus). 21,22 The venom antibodies are extracted from the ovine serum and subjected to papain digestion which cleaves off the larger, more immunogenic, and non-binding Fc (crystalline) portion of the antibody. The remaining active Fab (antibody binding) fragments are isolated via ion exchange and affinity chromatography columns and then lyophilized before distribution (Fig.…”