Clinical trial of two antivenoms for the treatment of Bothrops and Lachesis bites in the north eastern Amazon region of Brazil.
The efficacies of specific Bothrops atrox-Lachesis and standard Bothrops-Lachesis antivenoms were compared in the north eastern Amazon region of Brazil. The main aim was to investigate whether a specific antivenom raised against the venom of B. atrox, the most important Amazon snake species from a medical point of view, was necessary for the treatment of patients in this region. Seventy-four patients with local and systemic effects of envenoming by Bothrops or Lachesis snakes were randomly allocated to receive either specific (n = 38) or standard (n = 36) antivenoms. In 46 cases (24 in the standard antivenom group, 22 in the other) the snake was identified either by enzyme immunoassay or by examination of the dead snake, as B. atrox in 45, L. muta in one. Patients were similar in all clinical and epidemiological respects before treatment. Results indicated that both antivenoms were equally effective in reversing all signs of envenoming detected both clinically and in the laboratory. Venom-induced haemostatic abnormalities were resolved within 24 h after the start of antivenom therapy in most patients. The extent of local complications, such as local skin necrosis and secondary infection, was similar in both groups. There were no deaths. The incidence of early anaphylactic reactions was 18% and 19%, respectively for specific and standard antivenoms; none was life-threatening. Measurement of serum venom concentrations by enzyme immunoassay (EIA) confirmed that both antivenoms cleared venom antigenaemia effectively. EIA also revealed that one patient had been bitten by Lachesis muta, although the clinical features in this case were not distinctive.
Pardal
Pedro Pereira de Oliveira
PP
Hospital Universitário João de Barros Barreto, Belém-Pará, Brazil.
Souza
Suzana Medeiro
SM
Monteiro
Maria Rita de Cássia da Costa
MR
Fan
Hui Wen
HW
Cardoso
João Luiz Costa
JL
França
Francisco Oscar Siqueira
FO
Tomy
Sandra Corrallo
SC
Sano-Martins
Ida S
IS
de Sousa-e-Silva
Maria Cristina Cirillo
MC
Colombini
Mônica
M
Kodera
Nancy F
NF
Moura-da-Silva
Ana Maria
AM
Cardoso
Diva Ferreira
DF
Velarde
David Toledo
DT
Kamiguti
Aura S
AS
Theakston
Robert David
RD
Warrell
David A
DA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000997:Antivenins / Q000097:blood / Q000627:therapeutic use*; D001777:Blood Coagulation; D017837:Bothrops; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D003402:Creatine Kinase / Q000097:blood; D003435:Crotalid Venoms / Q000037:antagonists & inhibitors*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012909:Snake Bites / Q000097:blood / Q000188:drug therapy*; D016896:Treatment Outcome; D014757:Viper Venoms / Q000037:antagonists & inhibitors*; D017819:Viperidae
D000997:Antivenins; D003435:Crotalid Venoms; D014757:Viper Venoms; D003402:Creatine Kinase