Safety of low dose subcutaneous adrenaline used as prophylaxis against acute reactions to anti-venom serum (AVS) in patients bitten by snakes

Abstract

INTRODUCTION: Low dose subcutaneous adrenaline significantly reduces acute adverse reactions to AVS in patients envenomed following snake bite. OBJECTIVES: To further study the safety of low dose subcutaneous adrenaline. METHODS: We prospectively studied patients with snake bite envenoming in two units of the Colombo North Teaching Hospital, Ragama, from April 2000 to October 2001. Patients who satisfied inclusion criteria were given 0.25ml 1:1000 adrenaline subcutaneously immediately before administration of AVS. They were observed for adverse effects, and pulse and blood pressure (BP) were recorded before and at frequent intervals for one hour after giving adrenaline. In patients who developed reactions to AVS, subsequent pulse and BP measurements were not included for analysis. Results: 51 patients [M:F=35:16; mean age 34.8yrs (SD 14)] were included in the study. No significant changes in mean pulse rate or BP were observed following administration of subcutaneous adrenaline. Adverse reactions to AVS occurred in 15 (29.4%) patients. There were 4 (7.8%) other complications: one (2%) death due to suspected intracerebral haemorr-hage in a 65yr old man who also had coagulopathy, and developed an adverse reaction to AVS which required treatment with adrenaline; 3 (5.9%) patients, who also had coagulopathy, developed small haematomas at the subcutaneous injection site. CONCLUSIONS: Low dose subcutaneous adrenaline did not cause significant changes in pulse rate or BP. The 3 small haematomas could be directly attributed to the injection. Although the death is unlikely to be directly related to subcutaneous adrenaline, we suggest further studies on the safety of this prophylactic treatment before recommending its routine use.