For Agkistrodon contortrix (copperhead) envenomations, is there a difference between Fab AV (CroFab(r)) and F(ab’)2 AV (Anavip(r)) in the time or number of doses to achieve initial control of tissue injury effects?
A randomized clinical trial compared both AVs in envenomations by North American pit vipers (ClinicalTrials.gov, #00636116) . In a sub-group analysis of 21 copperhead snakebites  , there were no significant differences in time to initial control or number of loading doses to achieve initial control (one loading dose of either 10 vials of F(ab’)2 AV or 5 vials of Fab AV in most cases). The authors acknowledged the small sample size as limitation.
 Bush SP, Ruha A-M, Seifert SA, et al. Comparison of F(ab’)2 versus Fab antivenom for pit viper envenomation: a prospective, Fab antivenom for pit viper envenomation: a prospective, blinded, multicenter, randomized clinical trial. Clin Toxicol. 2015; 53(1):37–45. DOI: 10.3109/15563650.2014.974263  Gerardo CJ, Keyler DE, Rapp-Olson M, Dart RC. Control of venom-induced tissue injury in copperhead snakebite patients: a post hoc subgroup analysis of a clinical trial comparing F(ab’)2 to Fab antivenom. Clin Toxicol. 2022; 60(4):521-523. DOI: 10.1080/15563650.2021.1973489