Efficacy of anti-scorpion venom serum over prazosin in the management of severe scorpion envenomation

Background: Scorpion venoms cause a massive release of neurotransmitters. Either anti-scorpion venom serum (AScVS) or prazosin has been used in the management of severe scorpion envenomation. Aims: To compare the time taken for clinical recovery by patients with severe scorpion envenomation after AScVS therapy with that following prazosin therapy. Settings and Design: A prospective, open-labeled clinical trial was undertaken to compare the effects of the AScVS and/or prazosin on clinical recovery in scorpion-stung patients. Materials and Methods: Eighty-one patients from rural districts of Maharashtra presenting with severe scorpion envenomation were assigned to three treatment groups (AScVS: n = 28; prazosin: n = 25; AScVS + prazosin: n = 28). Severity of scorpion envenomation was graded using a proposed composite clinical scoring system to assess the therapeutic efficacy. AScVS was administered as an intravenous slow bolus, ranging from 40 to 100 ml, depending on the severity of envenomation. Prazosin was given as 1 mg every 3 h. Statistical Analysis Used: The non-parametric "Kruskal-Wallis" test was used in the statistical analysis and a P-value of 0.05 was considered significant. Results: Mean composite scores of patients from the three groups at the time of admission were comparable. Complete clinical recovery was noted in 4.14 ± 1.6 h and 19.28 ± 5.03 h in the subjects who were administered AScVS and prazosin, respectively (P < 0.001). There was no incidence of anaphylactic reaction to AScVS. Conclusions: Intravenous slow bolus of AScVS given based on the clinical severity of envenomation leads to early recovery than prazosin alone and is well tolerated.