Selecting a Treatment Regimen
ÎAnaphylaxis is an acute, life-threatening systemic reaction with varied mechanisms, clinical presentations, and severity that results from the sudden systemic release of mediators from mast cells and basophils. (B)
ÎThe more rapidly anaphylaxis develops, the more likely the reaction is to be severe and potentially life threatening. (C)
ÎPrompt recognition of signs and symptoms of anaphylaxis is crucial. If there is any doubt, it is generally better to administer epinephrine. (C)
ÎEpinephrine and oxygen are the most important therapeutic agents administered in anaphylaxis. Epinephrine is the drug of choice, and the appropriate dose should be administered promptly at the onset of apparent anaphylaxis. The consensus of experts is that, in general, treatment in order of importance is: epinephrine, patient position, oxygen, intravenous fluids, nebulized therapy, vasopressors, antihistamines, corticosteroids, and other agents. (C)
ÎAppropriate volume replacement either with colloid or crystalloids and rapid transport to the hospital is essential for patients who are unstable or refractory to initial therapy for anaphylaxis in the office setting. (B)
ÎMedical offices and facilities in which anaphylaxis is possible should have a well established plan of action to deal with anaphylaxis that is regularly practiced and the appropriate equipment to treat anaphylaxis. The more rapid the treatment, the better the outcome. Therefore, personnel in a medical office dealing directly with the patient's medical care should be familiar with the manifestations of anaphylaxis and be able to recognize an event quickly. Access to therapy should be immediately available. (B)
ÎPhysicians and office staff should maintain clinical proficiency in anaphylaxis management. (D)
ÎIn addition, telephone numbers for paramedical rescue squads and ambulance services might be helpful to have on hand. (C)
Epinephrine
ÎThe initial drug of choice is epinephrine. ÎThe concentration is 1:1000 and the adult dose is 0.2 to 0.5 mL (mg). ÎThe dose in a child is 0.01 mL (mg)/kg.
ÎThe time to highest blood concentration (Cmax), when studied in asymptomatic subjects, is shorter when injection is given intramuscularly in the vastus lateralis muscle (lateral thigh) than when it is administered either subcutaneously or intramuscularly in the deltoid muscle of the arm.
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Comment: There are no outcome data comparing these routes of administration during anaphylaxis. There are no data indicating that epinephrine is ineffective when administered either subcutaneously or intramuscularly in the deltoid muscle of the arm.
