Lifesaving Allergy Drug, Epinephrine, Out of Reach for Many in Need

Self-injectable epinephrine - used for treating anaphylaxis, a severe allergic reaction - is unavailable for adults and children in many countries, unavailable in doses for infants anywhere in the world and where it is available, it may be inadequately administered in some adults, especially women.

These findings were published in this month's Annals of Allergy, Asthma & Immunology, the scientific journal of the American College of Allergy, Asthma and Immunology (ACAAI).

Based on a survey of 75 allergists-immunologists in the 2003 to 2005 World Allergy Organization (WAO) House of Delegates, F. Estelle R. Simons, M.D., University of Manitoba, Winnipeg, Canada, finds that many areas of the world have no supplies of epinephrine kits for patients at risk of anaphylaxis, and nowhere in the world is there a autoinjector with a dose suitable for use in infants.

Anaphylaxis is a life threatening, often unexpected, allergic reaction that affects many parts of the body at once. Like other allergic reactions, anaphylaxis is the body's overreaction to a foreign substance that ordinarily is harmless. Symptoms of anaphylaxis include hives, swelling and flushing, difficulty breathing and wheezing, a swelling of the tongue, throat and nose, dizziness and a dangerous drop in blood pressure, nausea and cramping.

Epinephrine injections are first-line therapy for anaphylaxis and should be provided to all patients at risk of subsequent episodes of anaphylaxis according to new medical guidelines developed by the Joint Task Force on Practice Parameters of the ACAAI, the American Academy of Allergy, Asthma and Immunology (AAAAI), and the Joint Council on Allergy, Asthma and Immunology (JCAAI). The guidelines indicate that more than one dose is needed for approximately one third of individuals with anaphylaxis.

In Dr. Simons' survey, widespread availability of epinephrine autoinjectors for emergency self-treatment of anaphylaxis in the United States, Europe, Canada and Australia contrasted with limited availability in Asia, South America and Africa. Survey results revealed the cost for epinephrine autoinjectors were reported to range from U.S. $30 to U.S. $110, and could vary 2-fold within the same country. The purchase cost in some countries is equivalent to a month's salary for many patients.

The most common triggers of anaphylaxis worldwide are foods, as well as insect stings or bites, latex rubber, medications and exercise. In some world regions, unique anaphylaxis triggers are of relatively high importance, according to Dr. Simons. In the Asia-Pacific region, food triggers include buckwheat, bird's nest soup and royal jelly (ingested bee product), and sting and bite triggers include jellyfish, triatomid bugs and green ants.

The investigation also raises concerns for individuals at risk of anaphylaxis who may develop an anaphylaxis episode when traveling internationally, use their epinephrine, and subsequently be unable to obtain prescription refills.

Epinephrine injected by an autoinjector in the lateral aspect of upper thigh is the standard of care in the emergency self-treatment of anaphylaxis. The current recommendation includes both subcutaneous and intramuscular administration. The most widely used epinephrine product for self-administration in the United States is the EpiPen autoinjector.

In a separate report, Ted T. Song, D.O., Walter Reed Army Medical Center, Washington, D.C., and colleagues investigated whether EpiPen autoinjector, with a needle length of 1.42 cm, is sufficient for intramuscular delivery of epinephrine in men and women. Their findings showed that, since the distance from skin to muscle in the thigh is greater in women compared with men, the epinephrine autoinjector needle may not be long enough to deliver the drug to the intramuscular tissue in many women.

Recent studies have shown that intramuscular administration of epinephrine gives shorter time to maximal concentration compared with the subcutaneous route, but data is not available to establish one route as being superior over the other.

Investigators note that the increasing trend in obesity may mean that even fewer women would receive epinephrine adequately with the EpiPen autoinjector and that more men would also be affected. Physicians should be aware that many women and obese men will likely get the drug in their subcutaneous tissue and not in their intramuscular tissue.

Patient information on allergic diseases and anaphylaxis is available by calling the ACAAI toll free number at (800) 842-7777 or visiting its Web site at http://www.acaai.org, or the Food Allergy & Anaphylaxis Network (FAAN) at http://www.foodallergy.org.

The ACAAI is a professional medical organization comprising nearly 5,000 qualified allergists-immunologists and related health care professionals. The College is dedicated to the clinical practice of allergy, asthma and immunology through education and research to promote the highest quality of patient care.

Citations:

Simons, FE. Lack of worldwide availability of epinephrine autoinjectors for outpatients at risk of anaphylaxis. Ann Allergy Asthma Immunol 2005;94:534-538.

Song, TT, et al. Adequacy of the epinephrine autoinjector needle length in delivering epinephrine to the intramuscular tissues. Ann Allergy Asthma Immunol 2005;94:539-542.

Reference: Lieberman, P, et al. The diagnosis and management of anaphylaxis: An updated practice parameter. J Allergy Clin Immunol 2005; 115:S483-523.

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