Redback Antivenom

Indications: 

• Use is now regarded as controversial following the RAVE II trial where the benefits  were thought to be minimal relative to the risk of adverse effects
• Use should be discussed with a Clinical Toxicologist
• Generally considered when
  • There is persistent or intractable pain due to the bite despite aggressive  analgesic dosing including IV opiates
  • Considered in significant systemic features of latrodectism
    • (generalised pain  / autonomic features with severe sweating and haemodynamic lability)  

Formulation: 

• 500units of Red Back Spider antivenom each vial (contained in roughly 1-1.5mL)  

Dosage and Administration 

• Dilute 2 vials (1000units) into 100mL of Sodium Chloride 0.9% and infuse over 20  minutes IV
  • (dose the same for adults and children) 
• Antivenom should only be given in a resuscitation area with access to equipment  and adrenaline 

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.
• Delayed serum sickness; fever, rash, arthralgia and myalgia 

Pit Falls: 

• Provision of inadequate analgesic regime prior to use