Multicenter Study of a Mexican Polyvalent Antivenom – Antivipmyn Tri^â, in Bothrops Snake Bites in Colombia.

¹Otero, R.; ²Silva, J.J.; ¹Barona, J.; ¹Toro, M.F.; ¹Quintana, J.C.; ¹Díaz, A.; ¹Vásquez, I.C.; ¹Rodríguez, V.; ³Ayala, S.; ⁴Ramírez, E.; ⁵Ruiz, T.; ⁶Londoño, J.J.; ⁷Jaramillo, O.F.; ⁸Camargo, J.M. and the Regional Group on Antivenom Therapy Research (REGATHER).

1 Programa de Ofidismo / Escorpionismo, Facultad de Medicina, Universidad de Antioquia, Medellín.  Hospitals from 2 Leticia, 3 Quibdó, 4 Caucasia, 5 Puerto Berrío, 6 Vegachí, 7 Apartadó and 8 Tarazá.

To evaluate the efficacy and safety of a F(ab´)2 polyvalent (antibothropic / anticrotalic) antivenom produced in México (Instituto Bioclón S. A. de C.V.), tested previously in mice against snake venoms from Colombia, a clinical trial was performed during nine months in the hospitals from Leticia (Amazonas), Quibdó (Chocó), Caucasia, Puerto Berrío, Vegachí, Apartadó and Tarazá (Antioquia), testing also a new dosage regimen for Bothropsbites.  Fifty three patients fulfilled the criteria to be included in the study, 44 bitten by B. asper and nine by B. atrox, most of them (71.7%) at the low extremities, mainly in adults (72.2%) agricultural workers.  All of them had non-clottable blood on admission, 30 (56.6%) with local and 24 (45.35) with systemic hemorrhage (mainly gingival bleeding), six (11.3%) presented acute renal failure, six other had local abscess and one patient four years old complicated with compartment syndrome.  The final envenoming grade was mild in 13 (24.5%), moderate in 30 (56.6%) and severe in 10 patients (18.9%).  At the antivenom doses used in this study (5 vials for mild / moderate and 10 for severe envenoming), Antivipmyn Tri^â was 100% efficient to stop local and systemic bleeding within 6 – 12 h, and 94.3% efficient (50 patients) to restore blood coagulation within 24 h.  Two patients had prothrombin consumption with normal plasma fibrinogen concentration at 24 h, and two other presented recurrence of coagulopathy at 24 h and 48 h, respectively.  There were no statistical association (p > 0.05) between the time required to restore blood coagulation and the number of  antivenom vials (5 or 10) administered on admission.  Ten (18.9%) patients suffered early adverse reactions to antivenom, most of them mild (9 patients), moderate in one case (mild hypotension).  There were no deaths and four patients (7.5%) had sequelae, in three of them as a result of local necrosis.

Support: COLCIENCIAS, UNIVERSIDAD DE ANTIOQUIA and INSTITUTO BIOCLÓN S.A. DE C.V., MÉXICO.

Correspondence to: rafaotero@epm.net.co