Epinephrine, also known as adrenaline, is a hormone involved in your body’s “fight or flight” response. Epinephrine is produced by the adrenal glands, located on top of each of your kidneys.
Epinephrine helps maintain 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, notes the Cleveland Clinic.
Catecholamines are a type of hormone produced by the inner part of the adrenal gland called the medulla.
Emotions like fear, stress, or anger can trigger the release of epinephrine.
When epinephrine enters the bloodstream, it increases:
- Heart rate
- Cardiac output (the amount of blood pumped by the heart)
- Blood pressure
- Sugar metabolism
This helps 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, according to MedlinePlus:
Addison’s disease is a severe or total deficiency of the hormones made by the adrenal glands, including epinephrine, cortisol, and aldosterone.
Adrenal tumors, sometimes called pheochromocytoma, can cause too many adrenal hormones to be produced. In the case of pheochromocytoma, the hormones produced are epinephrine and noradrenaline.
This oversecretion of epinephrine can lead to a dangerous and severe elevation in blood pressure.
In different types of adrenal tumors, other hormones are overproduced, including cortisol, aldosterone, and androgens.
Epinephrine as Medication
Synthetic epinephrine is also used as a medication for the following, per MedlinePlus:
- 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 or swelling of the airway, notes the Mayo Clinic.
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, or bee stings
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 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, according to MedlinePlus.
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
Per MedlinePlus, 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.
