An open, randomized comparative trial of two antivenoms for the treatment of envenoming by Sri Lankan Russell's viper (Daboia russelii russelii)

Ariaratnam, C.Ariaranee; Sjöström, Lena; Raziek, Zeenia; Abeyasinghe, S.; Kularatne, M.; Arachchi, R.W.K.Kodikara; Sheriff, M.H.Rezvi; Theakston, R.David G.; Warrell, David A.

« Previous Next »Transactions of the Royal Society of Tropical Medicine and Hygiene
Volume 95, Issue 1 , Pages 74-80, January 2001

An open, randomized comparative trial of two antivenoms for the treatment of envenoming by Sri Lankan Russell's viper (Daboia russelii russelii)

C.Ariaranee Ariaratnam
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
Lena Sjöström
- Protherics PLC, Macclesfield, UK
Zeenia Raziek
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
S. Abeyasinghe
M. Kularatne
- Anuradhapura General Hospital, Anuradhapura, Sri Lanka
R.W.K.Kodikara Arachchi
- Anuradhapura General Hospital, Anuradhapura, Sri Lanka
M.H.Rezvi Sheriff
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
R.David G. Theakston
- World Health Organization Collaborating Centre for the Control of Antivenoms and Venom Research Unit, Liverpool School of Tropical Medicine, Liverpool, UK
David A. Warrell
- Address for correspondence: Professor D. A. Warrell, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford OX3 9DU, UK; phone +44 (0)1865 220968; fax +44 (0)1865 220984.
- Centre for Tropical Medicine, University of Oxford, Oxford, UK

Received 24 May 2000; received in revised form 29 June 2000; accepted 29 June 2000.

Abstract

Russell's viper (Daboia russelii russelii) is an important cause of morbidity and mortality in Sri Lanka. In a study in 1985, Haffkine equine polyspecific antivenom in doses up to 20 g proved ineffective in clearing antigenaemia and caused a high incidence of anaphylactoid reactions. A new, monospecific ovine Fabantivenom (PolongaTAb^™) has been developed against the venom of Sri Lankan Russell's viper and, to assess its safety and efficacy, we carried out (in 1997) an open, randomized comparison of this with the Hafikine antivenom currently in use in the country. Patients with systemic envenoming following Russell's viper bite were randomized to receive an initial intravenous dose of either 1 g of PolongaTAb (n = 23) or 10g of Haffkine antivenom (n = 20). One dose of PolongaTAb permanently restored blood coagulability in only 9 (41%) of 22 patients and 13 needed repeated doses, whereas the majority (; 70%) had restored coagulability after 1 dose of Haffkine antivenom. There was a tendency towards more rapid resolution of local swelling and systemic manifestations in the Hafifkine group. Venom antigenaemia was eliminated more quickly in the Haffkine group and ovine Fab was cleared from the circulation more rapidly than equine F(ab′)₂. To evaluate safety, patients were closely observed for adverse reactions. Following a severe reaction with Haffkine antivenom all subsequent patients in this group were treated prophylactically with hydrocortisone and chlorpheniramine. Despite this, the incidence of adverse reactions was significantly higher in the Haffkine group compared with the PolongaTAb group (81% compared with 48%) and 4 patients had a severe anaphylactic reaction in the former group. In conclusion, the new antivenom is safer than Haffkine antivenom but, to avoid repeated doses, an initial dose higher than 1 g is needed in the treatment of Sri Lankan Russell's viper envenoming. The safety of this larger dose is the subject of further studies.