The management of anaphylaxis is intramuscular adrenaline. The dose required for anaphylaxis is calculated based on the formula = 0.01 mL or mg of a 1:1000 dilution of adrenaline per kg of the patient (maximum dose = 0.5 mg = 500 mcg). Adrenaline auto-injectors allow for the management of anaphylaxis in community settings, and the amount of adrenaline delivered is based upon a pre-fixed dose within the pen. As can be seen in the table below:
- 150 mcg of adrenaline (e.g EpiPen Junior = green highlighted section) should be the dose prescribed to those weighing 10-20 kg
- 300 mcg of adrenaline (e.g. EpiPen = yellow highlighted section) should be the dose prescribed to someone weighing > 20 kg.
Currently there is only one brand of adrenaline auto-injector in Australia, and many patients/parents have recently experienced difficulties obtaining the EpiPen (300 mcg). Furthermore, there are no 500 mcg adrenaline auto-injectors currently available in Australia, which would be a better dose for patients > 50 kg. There is a different brand of adrenaline auto-injector (Emerade) currently being assessed by the TGA which has available three doses: 150 mcg (10-20 kg patient), 300 mcg (20-50 kg patient) and 500 mcg (for the > 50 kg patient). In the meantime, if you have an EpiPen Junior but you weigh > 20 kg, then speak with your GP/Allergist, as you should have the EpiPen 300 mcg as per ASCIA guidelines.