In patients with severe allergic reactions of grade II and above, epinephrine is the drug of choice for rescue treatment. Epinephrine should be administered as soon as possible after a patient has been diagnosed, or even highly suspected, of a severe allergic reaction of grade II and above. Epinephrine may also be considered for patients with severe abdominal pain and asthma following repeated exposure to allergens.
Intramuscular injection of epinephrine is preferred in most cases, with the site of intramuscular injection being the mid-lateral thigh.