We conducted a prospective , double-blind , randomized clinical trial , comparing late coagulopathy in snakebitten patients treated with F ( ab ' ) 2 with maintenance doses [ F ( ab ' ) 2/F ( ab ' ) 2 ] , or F ( ab ' ) 2 with placebo maintenance doses [ F ( ab ' ) 2/placebo ] , versus Fab with maintenance doses [ Fab/Fab ] .