Prophylactic medications for anti-venom anaphylaxis
Adrenaline prophylaxis prior to snake bite anti-venom may reduce
anaphylaxis and not be associated with significant adverse effects,
though it is difficult to generalise as there are a variety of
anti-venoms and only a small amount of evidence was identified. Two
trials in children and adults in Asia found that low dose prophylactic
adrenaline 0.25ml (1:1000) injected subcutaneously reduced the absolute
risk of severe reactions to anti-venom without significant adverse
effects (see Table 4, low certainty, supplement S7a).11Premawardhena
AP, de Silva CE, Fonseka MM, Gunatilake SB, de Silva HJ. Low dose
subcutaneous adrenaline to prevent acute adverse reactions to
antivenom serum in people bitten by snakes: randomised, placebo
controlled trial. BMJ 1999;318(7190):1041-1043.,22de
Silva HA, Pathmeswaran A, Ranasinha CD, Jayamanne S, Samarakoon SB,
Hittharage A, Kalupahana R, Ratnatilaka GA, Uluwatthage W, Aronson JK,
Armitage JM, Lalloo DG, de Silva HJ. Low-dose adrenaline,
promethazine, and hydrocortisone in the prevention of acute adverse
reactions to antivenom following snakebite: a randomised,
double-blind, placebo-controlled trial. PLoS Med 2011;8(5):e1000435.
It is unclear whether prophylactic intravenous corticosteroids or
histamine receptor blockers reduce anaphylaxis resulting from anti-venom
for snake bite because the certainty of evidence is very low. Two trials
in children and adults in Asia found that hydrocortisone alone or with
chlorpheniramine did not reduce the incidence of moderate to severe
reactions. (low certainty, supplement S7b).33de Silva HA,
Pathmeswaran A, Ranasinha CD, Jayamanne S, Samarakoon SB, Hittharage
A, Kalupahana R, Ratnatilaka GA, Uluwatthage W, Aronson JK, Armitage
JM, Lalloo DG, de Silva HJ. Low-dose adrenaline, promethazine, and
hydrocortisone in the prevention of acute adverse reactions to
antivenom following snakebite: a randomised, double-blind,
placebo-controlled trial. PLoS Med 2011;8(5):e1000435.,44Gawarammana
IB, Kularatne SA, Dissanayake WP, Kumarasiri RP, Senanayake N,
Ariyasena H. Parallel infusion of hydrocortisone +/- chlorpheniramine
bolus injection to prevent acute adverse reactions to antivenom for
snakebites. Med J Aust 2004;180(1):20-23.
Two trials in children and adults found that the antihistamine
promethazine did not reduce the incidence of anaphylaxis within 24 to 48
hours of antivenom (very low certainty, supplement S7c)55de
Silva HA, Pathmeswaran A, Ranasinha CD, Jayamanne S, Samarakoon SB,
Hittharage A, Kalupahana R, Ratnatilaka GA, Uluwatthage W, Aronson JK,
Armitage JM, Lalloo DG, de Silva HJ. Low-dose adrenaline,
promethazine, and hydrocortisone in the prevention of acute adverse
reactions to antivenom following snakebite: a randomised,
double-blind, placebo-controlled trial. PLoS Med 2011;8(5):e1000435.,66Fan
HW, Marcopito LF, Cardoso JL, França FO, Malaque CM, Ferrari RA,
Theakston RD, Warrell DA. Sequential randomised and double blind trial
of promethazine prophylaxis against early anaphylactic reactions to
antivenom for bothrops snake bites. BMJ 1999;318(7196):1451-1452.