For Clinicians

This section will be updated in the near future

Administration of antivenoms

Australian antivenoms are amongst the safest in the world. Many patients, even those with a past history of reaction to equine proteins, such as snake handlers, have had minimal or no problems with repeat antivenom therapy after premedication. They are, however, foreign protein, and the possibility of allergic reactions, including life threatening anaphylaxis, should always be considered and facilities be made available for dealing with such complications before the administration of antivenoms. Adrenaline is the treatment of choice for anaphylactic and anaphylactoid reactions, in conjunction with bronchdilators, fluid replacement etc.

Most antivenoms are given by the intravenous route, although redback spider antivenom and box jellyfish antivenom are more often used intramuscularly. Skin testing for allergy to antivenom is not recommended, as it is unreliable and may delay urgent therapy.

Antivenoms that are given intravenously should be diluted in at least 100ml of N. Saline, 5% dextrose or Hartmann’s solution immediately prior to administration. It should initially be administered slowly while the patient is observed for signs of allergic reaction. If no reaction is observed, then the rate of infusion may be increased. If the patient reacts to the antivenom, the rate may be slowed or the infusion ceased temporarily. If the reaction is more severe, then treatment with adrenaline, plasma volume expanders and beta agonists should be undertaken as required. The decision to recommence antivenom should be based on the clinical state of the patient. In the case of the patient with a known allergy to antivenom or to horse serum, the decision as to whether to withhold antivenom should again be clinically based, bearing in mind the resuscitation facilities available. The initial doses of antivenom recommended are based on the average amount of venom injected by each of the snakes concerned. There is evidence, however, that these doses may be insufficient to reverse coagulopathy associated with the bites of several Australian venomous snakes, notably the brown snake and the taipan. Larger initial doses should be considered if there is evidence of severe envenomation (multiple bites, rapidly progressive symptoms, large snakes).

The dose of antivenom for children should not be reduced according to their weight, since the amount of venom injected by the snake is independent of the victim’s size.

Note: the antivenom requirements of patients will vary considerably. Some patients with minimal envenoming will required no antivenom, whereas others may require multiple doses of antivenom.

Detailed information on the use of antivenoms is packaged with the individual antivenoms. If you require additional advice, contact the Information Centres on 13 11 26 (Australia wide) or CSL Ltd on (03) 9389 1911.

First aid references

  • Australian Resuscitation Council Guidelines, section 9.4: First Aid Guidelines-Envenomation. https://resus.org.au/guidelines/ accessed 25 Sept 2016.
  • Sutherland SK, Coulter AR, Harris RD. The rationalization of first aid measures for elapid snake bite. Lancet 1979;1: 183-6.
  • Sutherland SK, Coulter AR, Harris RD, Lovering KE, Roberts ID. A study of the major Australian snake venoms in the monkey (Macaca fascicularis). 1. The movement of injected venom, methods which retard this movement, and the response to antivenoms. Pathol 1981;13: 13-27.
  • Cox JC, Moisidis AV, Shepherd JM, Drane DP, Jones SL. A novel format for a rapid sandwich EIA and its application to the identification of snake venoms and enteric viral pathogens. J Immunol Methods 1992;146: 293-294.
  • Howarth DM, Southee AE, Whyte IM. Lymphatic flow rates and first-aid in simulated peripheral snake or spider envenomation. Med J Aust 1994;161: 695-700.
  • Sutherland SK, King K. Management of snake bite in Australia. Royal Flying Doctor Service of Australia Monograph Series No.1. 1991.
  • Sutherland SK, Leonard RL. Snake bite deaths in Australia 1992-1994 and a management update. Med J Aust 1995;163: 616-618.
  • Sutherland SK, Duncan AW. New first-aid measures of envenomation: with special reference to bites by the Sydney Funnel-web spider (Atrax robustus). Med J Aust 1980;1: 378-9.
  • Hartwick R, Callanan V, Williamson J. Disarming the box-jellyfish. Nematocyst inhibition in Chironex fleckeri. Med J Aust 1980;1: 15-20.
  • Exton DR, Fenner PJ, Williamson JA. Cold packs: Effective topical analgesia in the treatment of painful stings by Physalia and other Jellyfish. Med J Aust 1989;151: 625-6.

General references on envenoming

  • Welton RE, Williams DJ and Liew D. (2016), Injury trends from envenoming in Australia, 2000-2013. Intern Med J. Accepted Author Manuscript. doi:10.1111/imj.13297
  • Cogger HG. Reptiles and Amphibians of Australia. AH and AW Reed, Sydney. 1983.
  • Covacevich J, Davie P, Pearn J. (Eds) Toxic Plants and Animals: A Guide for Australia. Brisbane: Queensland Museum. 1987.
  • Edmonds C. Dangerous Marine Creatures. Reed Books, Frenchs Forest, NSW. 1989.
  • Gow GF. Snakes of Australia. Angus and Robertson, Sydney. 1976. Mascord R. Australian Spiders in Colour. AH and AW Reed, Sydney. 1983.
  • Meier, J. and White, J. Handbook of Clinical Toxinology.
  • Mirtschin P, Davies R. Snakes of Australia: Dangerous and Harmless. Hill of Content, Melbourne. 1992.
  • Morrison JJ, Pearn JH, Covacevich J, Nixon J. Can Australians identify snakes? Med J Aust 1983;2: 66-70.
  • Sutherland SK. Australian Animal Toxins: the creatures, their toxins and care of the poisoned patient. Melbourne: Oxford University Press, 1983;
  • Sutherland SK. Venomous Creatures of Australia. Oxford University Press, Melbourne. 1994.
  • Tibballs J. Diagnosis and treatment of confirmed and suspected snake bite: implications from an analysis of 46 paediatric cases. Med J Aust 1992;156: 270-274.
  • Tidswell F. Researches on Australian venoms, snake-bite, snake venom and antivenine, the poison of the Platypus, the poison of the red-spotted spider. N.S.W. Department of Public Health, Sydney 1906.
  • Underhill D. Australia's Dangerous Creatures. Reader's Digest. 1987. Weigel J. Guide to the Snakes of South-East Australia. Australian Reptile Park, Gosford. 1990.