Study did not start.

To determine if intravenous unfractionated heparin (with standard therapy) for treatment of anaphylaxis results in faster time to recovery.

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.

Inclusion Criteria:

• 18 years and older
• English speaking
• Meets one of the above definitions of anaphylaxis
• Signs/symptoms onset <12 hours will get epinephrine or will not get epinephrine because of contraindication to epinephrine administration.

Exclusion Criteria:

• History of Intracranial Hemorrhage at anytime
• Known Cerebral Vascular Lesion (i.e. Aneurysm, Arteriovenous malformation)
• Ischemic CVA within the last 3 months
• Suspected Aortic Dissection
• Active Bleeding
• Known Bleeding/Clotting Disorder
• Closed Head Trauma within the past 3 months
• Major Surgery (Abdominal/Thoracic) within the last 3 weeks
• Active GI Bleeding
• Currently taking Warfarin
• Allergy to Heparins
• History of Heparin-induced Thrombocytopenia (AHA contraindications to fibrinolytic therapy 2005, Micromedix 2007)