Rational use of anti-snake venom (ASV): trial of various regimens in hemotoxic snake envenomation.
BACKGROUND
Viperine snake bites cause hemotoxicity in the form of coagulation dysfunction. Optimal dose requirement of anti-snake venom (ASV) and duration of therapy in such situation have not yet been fully explored. Our aim in this study was to compare two low-dose continuous infusion regimes with the standard high dose intermittent bolus regime in treating systemic envenomation and preventing its recurrence.


METHODS
A prospective interventional study was conducted on 90 adult patients with snake bite with hemotoxicity. Patents were allocated into three treatment regimes, each regime being tried on 30 patients. Regimen I (standard high dose regimen) consisted of conventional, intermittent bolus dosage of 100 ml of ASV as a loading dose followed by 50 ml every six hours till whole blood coagulation time (CT) became normal. Regimen II consisted of 30 ml of ASV as a loading dose followed by 30 ml continuous infusion every six hours till two CTs at an interval of six hours were normal and a further dose of 30ml over 24 hours. Regimen III was similar to Regimen II in all aspects except that loading dose was 70 ml (instead of 30 ml).


RESULTS
In patients with mild envenomation, even though the average requirement of ASV was only marginally lower in Regimen II (128.6 ml) as compared to in Regimen I (137.5 ml), one patient on Regimen I had relapse of coagulation dysfunction. In patients with moderate envenomation, average requirement of ASV was 221.3 ml and 179 ml in Regimens II and III respectively, which was much less than in Regimen I (343.8 ml) (p values 0.05 and 0.01 respectively). Further, no patient receiving Regimen III had relapse of coagulation dysfunction. In severe envenomation, average dose of ASV required was almost similar in Regimens II and III, i.e., 213.7 ml and 233.7 ml respectively, as compared to 433.3 ml required in Regimen I (p values 0.02 and 0.001 respectively). However, time lapse for CT normalization was only 18 hours in Regimen III as compared to 23.6 hours and 24 hours in Regimens I and II respectively.


CONCLUSIONS
Regimens consisting of continuous intravenous infusion of ASV i.e., Regimen II in mild envenomation and Regimen III in moderate and severe envenomation are likely to make significant saving of ASV and reduction of recurrence of coagulation dysfunction.
Srimannarayana
J
J
Department of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry.
Dutta
T K
TK
Sahai
A
A
Badrinath
S
S
D000328:Adult; D000997:Antivenins / Q000008:administration & dosage*; D001778:Blood Coagulation Disorders / Q000188:drug therapy*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D011446:Prospective Studies; D012720:Severity of Illness Index; D012909:Snake Bites / Q000145:classification / Q000188:drug therapy* / Q000503:physiopathology; D013997:Time Factors
D000997:Antivenins