A RANDOMIZED, BLINDED, COMPARATIVE TRIAL OF ONE PEPSIN-DIGESTED AND 2WHOLE IGG ANTIVENOMS FOR BOTHROPS SNAKE BITES IN URABA, COLOMBIA

The therapeutic efficacy and the incidence of early antivenom reaction s (EARs) were compared in a clinical trial performed in 79 patients bi tten by Bothrops sp. in Uraba, Colombia. Patients were randomized into three groups according to the antivenom administered: A (n = 30, Buta ntan polyspecific, pepsin-digested Bothrops antivenom); B (n = 27, But antan polyspecific, whole IgG Bothrops antivenom); and C (n = 22, Colo mbian commercial, monovalent, whole IgG Bothrops antivenom). The group s were comparable in all clinical and epidemiologic aspects; 33 patien ts had mild, 22 moderate, and 24 severe envenoming. At the doses used (two, four, and six vials [10 ml/vial] for mild, moderate, and severe envenomings, respectively) there were no differences between the antiv enoms in restoring normal hemostatic parameters within 24 hr. The evol ution of local envenoming was comparable in the three groups. Serum ve nom/antivenom kinetics determined by ELISA showed a complete clearance of venom levels 1 hr after treatment in mild/moderate envenomings. In severe cases, venom levels remained detectable up to 24 hr and recurr ence of antigenemia was observed in some cases. Antivenom concentratio ns remained at high levels up to 24 hr of treatment. The incidence of EARs was significantly different in the groups: A (36.7%), B (11.1.%), and C (81.8%). There were no life-threatening anaphylactic reactions. We conclude that the efficacy of the three antivenoms was similar in neutralizing human Bothrops envenomings and that the production of who le IgG antivenoms by caprylic acid fractionation is a good alternative for reducing the incidence of EARs.