What Is Epinephrine?

Medically Reviewed

Allergists recommend that anyone with a serious allergy carry an epinephrine auto-injector with them.

Epinephrine, also known as adrenaline, is a hormone produced by the adrenal glands, which are located on top of each of your kidneys.

The hormone is necessary for maintaining a healthy cardiovascular system — it makes the heart beat more strongly, and diverts blood to tissues during times of stress.

Epinephrine is classified as a catecholamine hormone (as are dopamine and norepinephrine).

Catecholamines are a type of hormone produced by the inner part of the adrenal gland called the medulla.

Emotions such as fear, stress, or anger can trigger the release of epinephrine.

When the hormone enters the bloodstream, the following will increase:

  • Heart rate
  • Cardiac output
  • Blood pressure
  • Sugar metabolism

The above responses help to prepare your body for a "fight or flight" reaction, making you ready for rapid, strenuous activity.

Conditions Affected by Epinephrine

The following health conditions are linked to epinephrine levels:

Addison's disease is a severe or total deficiency of the hormones made by the adrenal glands, including epinephrine, cortisol, and aldosterone.

Adrenal tumors, some called pheochromocytoma, can cause too much adrenal hormones to be produced. In the case of pheochromocytoma, the hormones produced are epinephrine and noradrenaline.

This over-secretion of epinephrine can lead to a dangerous and severe elevation in blood pressure.

In different types of adrenal tumors, other hormones are over-produced, including cortisol, aldosterone, and androgens.

Epinephrine as Medication

Synthetic epinephrine is also used as a medication for the following:

  • To stimulate the heart during a cardiac arrest
  • As a vasoconstrictor (medication to increase blood pressure in cases of shock)
  • As a bronchodilator and antispasmodic in bronchial asthma
  • To treat a life-threatening condition called anaphylaxis

Anaphylaxis is a severe allergic reaction characterized by a drop in blood pressure and narrowing/swelling of the airways.

It can be caused by insect bites or stings, foods, medications, latex, and many other triggers, depending on a person's sensitivities.

Epinephrine is the first-response treatment for anaphylaxis. Prescribed by your doctor, it comes as a single dose in an auto-injector (such as an EpiPen).

Allergists recommend carrying an epinephrine auto-injector for serious allergies of almost any kind. Carrying one is especially important if you:

  • Have had a previous anaphylactic reaction
  • Have both food allergies and asthma
  • Are allergic to peanuts, tree nuts, fish, or shellfish

If you're not sure how serious your allergies are, your doctor can take a thorough medical history and perform blood and skin tests to find this out.

How Epinephrine Works

Epinephrine helps reverse life-threatening symptoms by relaxing the muscles in the airways and tightening the blood vessels.

The medicine is injected into muscles in the thigh during an anaphylactic reaction.

People with a severe allergy should know how to inject epinephrine, as should their family members and people they spend time with regularly.

Ask your allergist or immunologist to show you and your loved ones how to inject epinephrine.

It's important to note that other medications, such as antihistamines, don't reverse swelling of the airways or raise low blood pressure, so they won't help during anaphylaxis.

Epinephrine Side Effects

Common side effects of epinephrine include:

  • Anxiety
  • Restlessness
  • Dizziness
  • Shakiness

Rare but serious side effects of epinephrine include:

  • Abnormal heart rate or rhythm
  • Heart attack
  • Increase in blood pressure
  • Fluid buildup in the lungs

To help evaluate your risk of serious side effects, be sure to tell your allergist about all medical conditions you have.

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