Intravenous Heparin as an Adjunct for the Treatment of Anaphylactic/Anaphylactoid Reactions in the Emergency Department

Anaphylaxis is a potentially life-threatening entity that requires both immediate recognition and aggressive treatment. Although anaphylaxis is infrequent, comprising only 1% of approximately 1.03 million visits to the ED each year that are related to allergic reactions, it is none the less a generally under-recognized and under-treated disease, that is worthy of study due to the potential for a fatal outcome. Recently, there has been renewed interest in a commonly used and inexpensive drug (heparin) as a novel component of therapy for anaphylactic/anaphylactoid reactions. Heflin eft al. induced anaphylactoid reactions in pigs and compared intravenous unfractionated heparin in one treatment arm to standard therapy (intravenous epinephrine and diphenhydramine) versus placebo. The study revealed that heparin rapidly reversed the shock similar to that of standard emergency treatment. Of course this single study done in pigs will not change practice, but it does warrant further investigation into the role that heparin plays in anaphylaxis in humans.