Tiger Snake Antivenom

Tiger Snake antivenom (equine IgG Fab) can be used to treat envenomation from the Tiger snakes in Australia, these include the Common and western Tiger snake, Stephen’s banded snake, pale-headed snake, broad-headed snake, rough-scaled snake, copperhead snake and the small-eyed snake

Indication:

• Clinical evidence of envenomation
• Tiger snake and rough-scaled snake: laboratory evidence of complete or partial venom-induced consumptive coagulopathy (VICC), neurotoxicity and myotoxicity
• Copperhead: paralysis and occasional myotoxicity
• Pale-headed and broad-headed snake: VICC but not paralysis or myotoxocity
• Small-eyed snake – myotoxicity

Contraindication:

• No absolute
• Increased Risk of anaphylaxis in patients previously treated with antivenom or those who are suspected of equine sera allergy

Administration:

• Place the patient in a monitored area where anaphylaxis can be managed
• Administer 1 ampoule diluted in 500ml of 0.9% saline IV over 20 minutes (the dose is the same for adults and paediatrics – snakes don’t envenomate less because its a child)

Adverse drug reactions:

• Anaphylaxis: Cease antivenom infusion, treat as per anaphylaxis with oxygen, IV fluids and IM adrenaline. Recommence antivenom infusion when anaphylaxis has resolved. Rarely will ongoing administration of adrenaline be required to complete the antivenom infusion.
• Serum Sickness: A benign and self limiting complication occurs 5-10 days after antivenom, symptoms include fever, rash, arthralgia and myalgia. Oral steroids for 5 days may ameliorate symptoms (e.g. prednisolone 50mg/day in adults and 1mg/kg in children). All patients should be warned about this complication who receive antivenom.

Controversies:

• Tiger snake antivenom halts the progression of paralysis but established neurotoxicity is not reversed
• Envenoming by the Hoplocephalus spp (Stephen’s banded snake, pale-headed snake and broad-headed snake) resemble that of the brown snake and therefore it is possible to give brown snake antivenom in these particular cases if no tiger is available
• The use of Fresh Frozen Plasma or Cryoprecipitate: When used after antivenom has been associated with a quicker recovery of VICC but not with earlier hospital discharge. The use of these products in envenomation has not been well defined and should be used at the recommendation of a toxicologist.

References

• Tox Library – Tiger Snakes
• Brown SGA, Caruso N, Borland M et al. Clotting factor replacement and recovery for snake venom-induced consumptive coagulopathy. Intensive Care Medicine 2009; 35(9):1532-1538
• Isbister GK, Buckley NA, Page CB et al. A randomised controlled trial of fresh frozen plasma for treating venom-induced consumption coagulopathy in cases of Australian snakebite (ASP-18). Journal of Thrombosis and Haemostats 2013; 11:1310-1318
• Isbister GK, Brown SG, MacDonald E et al. Current use of Australian snake antivenoms and frequency of immediate-type hypersensitivity reactions and anaphylaxis.  Medical Journal of Australia 2008; 188:473-476.
• Isbister GK, Duffull SB, Brown SGA. Failure of antivenom to improve recovery in Australian snakebite coagulopathy. Quarterly Journal of Medicine 2009; 102(8):563-568
• Isbister GK, O’Leary MA, Eliott M, Brown SGA. Tiger snake (Notches spp.) envenoming: Australian Snakebite Project (ASP-13). Medical Journal of Australia 2012; 197(3):173-177
• Isbister GK, White J, Currie BJ et al. Clinical effects and treatment of envenoming by Hoplocephalus app. snakes in Australia: Australian Snakebite Project (ASP-12). Toxicant 2011; 58:634-640