Comparative study of the efficacy and safety of two polyvalent, caprylic acid fractionated [IgG and F(ab')2] antivenoms, in Bothrops asper bites in Colombia

Toxicon. 2012 Feb;59(2):344-55. doi: 10.1016/j.toxicon.2011.11.017. Epub 2011 Nov 29.


The efficacy and safety of two polyvalent horse-derived antivenoms in Bothrops asper envenomings were tested in a randomized, double-blind, clinical trial performed in Colombia. Both antivenoms were manufactured from the same pool of hyperimmune plasma. Antivenom A was made of F(ab')2 fragments, generated by pepsin digestion and caprylic acid precipitation, whereas antivenom B consisted of whole IgG molecules produced by caprylic acid precipitation followed by ion-exchange chromatography. Besides the different nature of the active substance, antivenom B had higher protein concentration, slightly higher turbidity and aggregate content. No significant differences were observed in the efficacy of antivenoms. Both halted local and systemic bleeding (P = 0.40) within 6-12 h of treatment in 100% of the cases, and restored blood coagulation (P = 0.87) within 6-24 h in 84.7% of patients, and within 48 h in all of them, in agreement with restoration of plasma fibrinogen concentration. Venom concentrations in serum dropped significantly (P < 0.001), to very low levels, 1 h after antivenom infusion. Nevertheless, eight patients (11.1%), four for each antivenom, presented recurrence of venom antigenaemia at different times, from 6 to 96 h, with clinical significance (recurrent coagulopathy) only in one group B patient (2.9%). Serum creatine kinase (CK) activity was increased, as a consequence of local myonecrosis. There was no significant difference (P = 0.51) in the incidence of early adverse reactions to antivenom administration (28.9% for patients of group A and 20.6% for patients of group B), most of the reactions being mild, mainly cutaneous. The most frequent complications were cellulitis (16.7%), abscess formation (5.6%), acute renal failure (8.3%), and compartmental syndrome (5.6%). In conclusion, IgG and F(ab')2 antivenoms, prepared by caprylic acid fractionation, presented similar efficacy and safety profiles for the treatment of B. asper envenomings in Colombia.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Animals
  • Antivenins / therapeutic use*
  • Blood Coagulation
  • Blood Coagulation Disorders / drug therapy
  • Bothrops / metabolism*
  • Caprylates / pharmacology
  • Chemical Fractionation / methods
  • Chromatography, Ion Exchange / methods
  • Colombia
  • Crotalid Venoms / metabolism
  • Double-Blind Method
  • Drug Evaluation
  • Drug-Related Side Effects and Adverse Reactions / metabolism*
  • Female
  • Fibrinogen / analysis
  • Hemorrhage / drug therapy
  • Humans
  • Immunoglobulin Fab Fragments / therapeutic use
  • Immunoglobulin G / therapeutic use
  • Incidence
  • Male
  • Pepsin A / metabolism
  • Snake Bites / drug therapy*
  • Treatment Outcome


  • Antivenins
  • Caprylates
  • Crotalid Venoms
  • Immunoglobulin Fab Fragments
  • Immunoglobulin G
  • Fibrinogen
  • Pepsin A
  • octanoic acid