Funnel Web Antivenom

Liverpool Hospital Emergency Department


  • Suspected funnel web spider envenoming and signs of severe envenoming
  • Cholinergic and adrenergic features
    • (sweating, salivation, lacrimation, piloerection,  hypertension etc.) 
  • Paraesthesia / fasciculations / spasms
  • Myocardial dysfunction and dysrhythmia
  • Pulmonary oedema
  • Agitation anxiety and coma
  • Abdominal pain nausea and vomiting

(Have to hand in any BIG BLACK SPIDER BITE!!!!!!) 

Formulation: Stock 2 

  • 125 units of funnel web spider antivenom each vial 

Dosage and Administration 

  • Administer in a critical care area with access to adrenaline and resuscitation equipment
  • Recommended dose is 2 vials of Funnel Web antivenom (dose the same for both adults and  children) 
  • Dilute in 1:10 NaCl 0.9% or Hartmanns or 1:5 if at risk of fluid overload or paediatric cases
  • Gently swirl or invert to completely dissolve, it may take up to 10 minutes to  achieve colourless solution. 
  • Administer by slow IV injection
  • Can also be given undiluted as IV slow push over 2 minutes
  • Generally additional doses are not required however discuss with a clinical toxicologist in  particular if inadequate response
  • Can be given in paediatrics or pregnancy 

Side Effects 

  • Anaphylaxis 
  • If there is an acute allergic or anaphylactic reaction temporarily stop the infusion  and treat accordingly then recommence the infusion at a slower rate.
  • Rarely adrenaline infusion may be needed to complete the full dosage of antivenom
  • Delayed serum sickness; fever, rash, arthralgia and myalgia
  • Lymphadenopathy, albuminuria, arthritis, nephritis and vasculitis 

Pit Falls 

  • Severe funnel web envenoming may develop catechol related myocardial dysfunction  requiring inotropic support – consult Clinical Toxicologist
  • Admit all patients who have required antivenom and monitor for 12-24 hours until  envenoming has resolved
  • Warn re serum sickness when discharging