Anaphylaxis - treatment with IM epinephrine is safer than IV


Published Online: August 29, 2014

Anaphylaxis is a serious allergic reaction that may cause death. Epinephrine is the treatment of choice for the management of anaphylaxis, and fatal anaphylaxis has been associated with delayed epinephrine treatment. However, epinephrine administration for the management of anaphylaxis can be challenging and has been associated with the risk of overdose and cardiovascular complications such as heart attacks and abnormal heart rhythms (arrhythmias). Two common methods of administering epinephrine are intravenous (IV), injected directly into a vein, and intramuscular (IM), injected into the muscle. Until now, the relative safety of these two methods of administration had not been directly compared. Importantly, persons at risk of anaphylaxis carry self-injectors of epinephrine designed to deliver the medication IM.

In an article recently published in The Journal of Allergy and Clinical Immunology: In Practice, Campbell and colleagues compared rates of cardiovascular complications and epinephrine overdoses associated with IV and IM epinephrine administration among emergency department (ED) patients with anaphylaxis.

The authors studied 573 patients who were treated for anaphylaxis in the ED. A total of 362 doses of epinephrine were administered to 301 patients. There were 8 cardiovascular complications and 4 overdoses, occurring in 8 different patients. All overdoses occurred when epinephrine was administered via IV bolus (given all at once rather than slowly over a period of time). Cardiovascular complications were more likely when epinephrine was given IV compared to IM (3 out of 30 (10%) doses of IV bolus epinephrine compared to 4 out of 316 (1%) doses of IM epinephrine). Similarly, overdose occurred with 4 of 30 (13%) doses of IV bolus epinephrine compared with 0 of 316 (0%) doses of IM epinephrine.  

These finding indicate that the risk of overdose and cardiovascular complications are much higher with IV bolus epinephrine administration. They also support the safety of IM epinephrine in the treatment of anaphylaxis.


The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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