Which of the following statements is correct regarding F(ab’)2 AV (Anavip)? A. It is an ovine-derived antivenom B. The elimination half-life is longer than polyvalent immune Fab AV (Crofab) C. The recommended control dose is 4-6 vials followed by maintenance doses of 2 vials every 6 hours x 3 doses D. Recent studies have shown HIGHER rates of late coagulopathy when compared to polyvalent immune Fab AV (Crofab)
Answer – B. The elimination half-life of Anavip is 133 hours compared to 12-23 hours with Crofab. Anavip is an equine derived antivenom that has been associated with lower rates of late coagulopathy when compared to Crofab. Dosing of Anavip is a control dose of 10 vials without scheduled maintenance dosing but an additional 4 vials may be used as needed if symptoms re-emerge.
Wilson BZ, Bahadir A, Andrews M, et al. Initial Experience with F(ab’)2 Antivenom Compared with Fab Antivenom for Rattlesnake Envenomations Reported to a single poison center during 2019. Toxicon. 2022;209:10-17. doi:10.1016/j.toxicon.2022.01.007
Contributed by: Scott Turner, PharmD, PGY2 Emergency Medicine Pharmacy Resident, UF Health Jacksonville on behalf of the Florida Poison Information Center Network