Epinephrine in Anaphylaxis: Too Little, Too Late

Jay Adam Lieberman; Julie Wang


Curr Opin Allergy Clin Immunol. 2020;20(5):452-458. 

In This Article

Reasons for Low Utilization of Epinephrine

There are numerous reasons for underutilization of epinephrine. On the provider side, these can be broken down into themes, such as gaps in knowledge, lack of implementation, and lack of follow-up care.[26] Gaps in knowledge can be attributable to poor anaphylaxis recognition, poor knowledge of treatments choices, or poor knowledge of adequate dosing, which can be easily defined by knowledge assessment tools.[26] Lack of implementation is less easily defined. This may exist when providers are knowledgeable about anaphylaxis and the treatment but choose not to give epinephrine. Separating knowledge from real life actions is challenging. For example, one study showed that implementing an order-set and a 1-h education session in one ED, led to improvements, but epinephrine use only increased from 33 to 51%.[32] Understanding reasons for this is difficult. For example, even when allergists are surveyed, there are gaps in when they would consider a case anaphylaxis but choose not to treat with epinephrine.[33] Finally, lack of follow-up care suggests patients with an anaphylactic event are not given prescriptions for autoinjectors or not referred to a specialist for follow-up care, and therefore, may not be prepared for future reactions.[24,26,34,35]

Like providers, for patients, lack of knowledge (e.g. confusion on the diagnosis of anaphylaxis or lack of understanding of autoinjector device) may be one factor that leads to underuse of epinephrine. However, patients/caregivers face other obstacles that likely affect their use of epinephrine. These can be outlined as follows.

Not Having Epinephrine Autoinjector Available

This has been a theme affecting anaphylaxis management for years.[26] One major global hurdle is that autoinjectors are still not readily available worldwide.[36] However, even in patients prescribed an autoinjector, surveys continue to show poor prescription fill and carriage rates.[37–39]

Having Epinephrine Available but not Using it During Reaction

This issue does not appear to be as common as lacking the autoinjector during a reaction. However, based on survey results, there are patients who had an autoinjector available, but did not use during a severe reaction. Most commonly this was because of the patient/caregiver not considering the reaction serious; other reasons were because of lack of understanding of how to use the device or fear of the medication or that it would escalate the situation.[38,40]

Underdosing of Epinephrine

Even if epinephrine is administered, there is a concern that in some cases the dose may not be adequate. There are no dose-ranging studies of epinephrine in anaphylaxis, but guidelines suggest an intramuscular dose of 0.01 mg/kg to a maximum of 0.5 mg in adults and 0.3 mg in children.[5] Given current epinephrine autoinjectors have limited dosing options, there is clearly a likelihood that the dose will be inadequate in some patients.[41] In addition, given that needle lengths are not adjustable, there is a chance that in some patients, the device will deliver the medication subcutaneous rather than intramuscular.[42,43]