A shot of adrenalin

For many people a bee sting is a painful annoyance, but for those with a severe allergy to the insect’s toxin, the episode could rapidly progress into a life-threatening situation.

The danger is anaphylaxis, and it’s not just limited to insect stings. Other common triggers include shellfish, peanuts, tree nuts, cow’s milk, eggs, latex and medications — most commonly penicillin.

Severe allergic reactions are rare, but when they occur it takes just seconds for anaphylactic shock to set in, requiring emergency treatment. For those at risk for this type of reaction, an epinephrine auto-injector could mean the difference between life and death.

An epinephrine auto-injector is a fast-acting shot of adrenalin that can be self-administered, and — when used correctly — can help normalize blood pressure and make breathing easier in the event of anaphylactic shock.

New findings published in the April issue of the Annals of Allergy, Asthma & Immunology by an international team of researchers from the Virginia Commonwealth University schools of Medicine and Pharmacy, the University of Manitoba in Canada and the University of Tennessee, suggest that the incidence of unintentional injection with epinephrine auto-injectors is increasing. Read the abstract here.

The team examined 26 reports in peer-reviewed medical journals that were published within the past 20 years and identified 69 incidents of unintentional injection of epinephrine. About 70 percent of them had occurred within the past six years.

“Anyone who may be required to use an epinephrine auto-injector needs to be aware of the risk of unintentional injection and be trained in its proper use,” said Edward J. Read Jr., M.D., assistant clinical professor in the Department of Emergency Medicine in the VCU School of Medicine. “This needs to be at initial prescription and also at a regular follow-up training session because there is often a significant gap between initial dispensing of the auto-injector and its use in an emergency.” Read led the VCU portion of the study.

The typical auto-injector has the appearance of a large pen. Misuse occurs when users try to inject themselves or another person with the wrong end of the device, inadvertently injecting their thumb or finger instead. The shot is usually administered to a patient’s leg.

According to Read, the projected rate of unintentional injections is one in 50,000; however, the true figure is likely much higher than indicated in the study which only looked at published reports. 

“The consequence for the person receiving the unintentional injection is not usually too severe. The bigger risk may well be the ‘lost dose,’ the fact that the epinephrine is no longer available to administer properly to the person urgently needing it,” said Read.  

“Our findings reinforce a widely held belief that the current self-administration devices for anaphylaxis are not particularly user-friendly,” said Read. Read, together with a team of researchers from various institutions, is working with Richmond-based company Intelliject, Inc., to develop an epinephrine delivery system specifically designed to address these concerns and to minimize the likelihood of unintentional injections, as well as other use errors. 

According to the American College of Allergy, Asthma and Immunology, anyone can experience an anaphylactic reaction, however, those who have allergies and/or asthma and a history of severe allergic reaction are at increased risk.

Some symptoms of anaphylaxis include hives, itching and redness of the skin, lips, eyelids or other parts of the body or itching of the throat, tongue and mouth, and wheezing and difficulty breathing. Swelling of the tongue, throat and nose, nausea, vomiting, diarrhea, or abdominal cramping can occur. In very severe cases, dizziness and fainting or loss of consciousness may occur, which can progress to shock and heart failure.

Read and his collaborators currently have research under way to try to further delineate the true number of unintentional injections. 

The study was led by F. Estelle R. Simons, M.D., with the Department of Pediatrics and Child Health at the University of Manitoba in Canada. Eric S. Edwards, a postdoctoral candidate in the VCU School of Pharmacy and cofounder of Intelliject Inc., and Phillip L. Lieberman, M.D., with the University of Tennessee College of Medicine, also contributed to this work.

The Annals of Allergy, Asthma & Immunology is the scientific journal of the American College of Allergy, Asthma and Immunology.