Epinephrine (adrenaline) is the treatment of choice for anaphylaxis. While other medications, including H1-antihistamines, H2-antihistamines, corticosteroids, and inhaled beta-2 agonists are often used to treat anaphylaxis in the emergency setting, none of these medications has been shown to reverse anaphylaxis. Fatal anaphylaxis is related to the delayed use of epinephrine. In community settings, epinephrine is available as an auto-injector in two doses, 0.15 mg and 0.3 mg. The recommended dose for children is 0.01 mg per kilogram. For infants at risk of anaphylaxis in the community, there are few options with regard to providing an optimal epinephrine dose for first-aid treatment. The Canadian Society of Allergy and Immunology (CSACI) therefore recommends, for the child weighing less than 15 kg, given the lack of a suitable alternative, prescribing the 0.15 mg epinephrine autoinjector. Adverse effects of an epinephrine dose of 0.15 mg given intramuscularly in infants or children weighing less than 15 kg are expected to be mild and transient at the plasma epinephrine concentrations achieved; therefore, these effects need to be measured against the consequences of not receiving epinephrine at all, which can include fatality.
Halbrich, M., Mack, D. P., Carr, S., Watson, W., & Kim, H. (2015, June 12). CSACI position statement: Epinephrine auto-injectors and children < 15 kg. Allergy, Asthma and Clinical Immunology. BioMed Central Ltd. https://doi.org/10.1186/s13223-015-0086-9