Pharmacologic Management of Acute Anaphylaxis

Abstract

Prompt recognition and treatment of anaphylaxis are essential to assuring favorable clinical outcomes. Anaphylaxis has been defined as a serious allergic reaction that is rapid in onset and may cause death and is characterized by acute respiratory compromise and/or profound hypotension after injection or ingestion of an allergen. Once recognized, epinephrine is the treatment of choice and must be administered immediately, preferably via the intramuscular (IM) route in the anterolateral thigh and repeated every 5 min until clinical improvement. Other key measures include calling the emergency response team for assistance (i.e., 911); placing hypotensive patients in the supine position to improve cardiac output; maintenance of the airway; high flow oxygen; obtaining intravenous access; fluid resuscitation with crystalloid (i.e., normal saline) in the absence of a favorable response to IM epinephrine; and failing a response to all aforementioned interventions including IM epinephrine, intravenous administration of epinephrine, or a vasopressor agent (e.g., vasopressin). Glucocorticoids and antihistamines are generally recommended but considered secondary ancillary drugs. Following recovery, patients must be educated on future avoidance of causative agents and trained on self-administration of epinephrine with an auto-injector device, for future anaphylactic events after unforeseen allergen exposure.