How does epinephrine help anaphylaxis

When epinephrine is given by injection, it increases your heart rate and blood pressure as well as relaxes the muscles in the airways.

Epinephrine reverses the symptoms of anaphylactic shock and temporarily halts the allergic reaction. Epinephrine is the ONLY drug that will reverse anaphylaxis and should be given as soon as symptoms appear. Any delay in giving epinephrine greatly increases the chance of hospitalization. Deaths due to anaphylaxis are often associated with either delaying the use of epinephrine or not using it at all. Antihistamines will not reverse anaphylaxis.

Doctors recommend using an epinephrine auto-injector as the first treatment at the sign of any severe allergic reaction. Epinephrine will not harm a patient. Antihistamines only treat a few minor symptoms of anaphylaxis — like hives. Antihistamines take about 30 or more minutes to take effect, which is far too long to treat an urgent medical condition.

One more time: epinephrine will treat a life-threatening allergic reaction — antihistamines will not. After some people experience an anaphylactic reaction, they will have a secondary, or biphasic reaction. After someone appears to recover from an anaphylactic reaction, a second reaction can occur without any additional exposure to an allergen up to 12 hours later or longer.

While symptoms are often milder than the initial reaction, they often require a second dose of epinephrine. This is the main reason why you need to go to the emergency room after using epinephrine. People at risk for anaphylaxis should carry two epinephrine auto-injectors at all times.

The epinephrine auto-injector needs to be used at the first sign of symptoms and seek follow-up medical care right away. Thirty-percent of people need a second dose of epinephrine to relieve their symptoms. Studies show that many parents are hesitant to give their child epinephrine.

They are often fearful of hurting their child or themselves as the primary reason. Sometimes they are uncertain if their child is having a dangerous allergic reaction. Parents need to remember that epinephrine is the life-saving treatment for an allergic reaction and must be given without delay. A helpful tool when it comes to managing and treating anaphylaxis, especially in children, is an Allergy and Anaphylaxis Emergency Plan.

Epinephrine is a hormone made by the adrenal glands. It works within minutes to prevent progression and reverse the symptoms of anaphylaxis. The answer is yes. Epinephrine should be administered without delay if there is any concern or suspicion of anaphylaxis, because the risk of an untreated severe allergic reaction outweighs the risk of inappropriately receiving epinephrine.

Furthermore, delays in epinephrine administration can result in more severe reactions, and possibly even death. Individuals carrying an epinephrine autoinjector EpiPen, Auvi-Q, Adrenaclick, others should use it immediately if they suspect an anaphylactic reaction, and then call Anyone who has been treated with epinephrine after an anaphylactic reaction should be transported by ambulance to an emergency room, where they will continue to be monitored.

This is because some people who have had an anaphylactic reaction may have protracted anaphylaxis, with symptoms lasting several hours or possibly days. Others may have biphasic anaphylaxis, which is a recurrence of symptoms several hours or possibly days after symptoms resolve, even without further exposure to the allergic trigger. For both protracted and biphasic anaphylactic reactions, the first-line treatment remains epinephrine.

Biphasic reactions can occur up to three days after the initial anaphylactic reaction, which means you may develop symptoms even after being discharged from the emergency room. There is no substitute for epinephrine, which is the only first-line treatment for anaphylaxis. Neither antihistamines nor glucocorticoids work as quickly as epinephrine, and neither can effectively treat the severe symptoms associated with anaphylaxis. However, antihistamines such as diphenhydramine Benadryl or cetirizine Zyrtec , glucocorticoids like prednisone, or a combination, may be used in addition to epinephrine in some cases of anaphylaxis, after epinephrine is administered.

Antihistamines can relieve some symptoms of a mild non-anaphylactic allergic reaction, such as hives, itching or flushing, usually within an hour or two after they are given. Glucocorticoids take even longer to have an effect, so they are not useful for the treatment of any acute symptoms. As noted in anaphylaxis practice guidelines published in the Journal of Allergy and Clinical Immunology , neither antihistamines nor glucocorticoids have been shown effective in preventing biphasic anaphylaxis, so they should not be given routinely after immediate allergy symptoms have resolved.

However, some patients may benefit from a short course of glucocorticoids, for example if they had severe facial swelling or asthma symptoms related to their anaphylactic reaction. Anyone who has had anaphylaxis is at increased risk of experiencing anaphylaxis again. The auto-injector should be injected either intramuscularly or subcutaneously into the anterolateral aspect mid to upper area of the thigh, through clothing if necessary.

The injection should not be given into the buttock, as this may not provide effective treatment of anaphylaxis and may increase the risk of Clostridial infection. Caregivers of young children who may be uncooperative and kick or move during an injection should be instructed to hold the leg firmly in place to limit movement before and during the injection. Adverse effects include increased heart rate, palpitations, sweating, nausea and vomiting, difficulty breathing, pallor, dizziness, weakness or shakiness, headache, apprehension, nervousness, or anxiety.

These signs and symptoms usually subside rapidly, especially with rest. Patients with coronary artery disease could experience angina, while those with diabetes may develop increased blood glucose levels following epinephrine administration. Before use, patients should be instructed to make sure the solution in the auto-injector is clear and colorless.

If the solution is discolored, cloudy, or contains particles, the auto-injector should be replaced. Expiration dates are printed on the sides of the auto'injectors. As the effectiveness of epinephrine may decrease after the expiration date, patients should be instructed to promptly refill their prescription before it.

Mylan is expected to release a generic formulation of EpiPen that will cost half of the brand-name version sometime in September Patient information and support is available from the following national patient support groups for Australia and New Zealand:. ASCIA resources are based on published literature and expert review, however, they are not intended to replace medical advice.

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