Epinephrine (Adrenaline)

What epinephrine (adrenaline) is and how it works

Epinephrine (also called adrenaline) is a hormone and medicine that rapidly narrows blood vessels, relaxes airway muscles, and strengthens the heartbeat. As an auto-injector, it is the first-line emergency treatment for anaphylaxis -- a sudden, severe, potentially life-threatening allergic reaction to things like insect stings, foods, medicines, or other triggers. (1) (2)

An epinephrine auto-injector is designed to be used quickly by the person having the reaction, or by someone nearby, without needing special training beyond following the device instructions. Using it correctly -- in the outer thigh only, never in the hands, feet, digits, or buttock -- and always calling emergency services straight afterwards, are both genuine safety essentials, not just general advice.

Mechanism of action: how epinephrine (adrenaline) works

Epinephrine is a non-selective agonist at alpha-1, alpha-2, beta-1, and beta-2 adrenergic receptors. In anaphylaxis, alpha-1 agonism reverses vasodilation and reduces mucosal oedema, beta-1 agonism increases heart rate and contractility, and beta-2 agonism relaxes bronchial smooth muscle and reduces further mediator release from mast cells and basophils. (1) (2) (4)

What epinephrine (adrenaline) is used for

Before taking epinephrine (adrenaline)

Do not take / not appropriate for

• There are no known absolute contraindications to using an epinephrine auto-injector during a genuine life-threatening allergic emergency -- the benefit of stopping anaphylaxis outweighs other risk factors in that moment. (all countries) (2) (4)
• Never inject into the buttock, hands, feet, digits, ears, nose, or genitalia -- only the outer (anterolateral) thigh is a correct injection site. (all countries) (1) (2) (6)

Tell your clinician about

• Any heart condition, including coronary artery disease, arrhythmias, or high blood pressure -- this does not stop epinephrine being used in a genuine anaphylactic emergency, but your clinician will want to know and may monitor you more closely.
• Diabetes, thyroid disease, or narrow-angle glaucoma.
• All other medicines you take, especially beta-blockers, antidepressants (including MAO inhibitors and tricyclics), or thyroid hormone.
• Any allergy to sulfites, since some formulations contain sodium metabisulfite.
• Whether you are pregnant or breastfeeding -- this does not prevent epinephrine being used for a genuine allergic emergency.

How to take epinephrine (adrenaline)

• Use immediately at the first signs of a severe allergic reaction (anaphylaxis) -- do not wait to see if symptoms improve on their own.
• Inject into the middle of the outer thigh, through clothing if necessary; hold in place for the duration specified in your device's instructions.
• Hold a young child's leg firmly and limit movement during and immediately after injection, to avoid needle-related injury.
• Always call emergency services immediately after use and say the word 'anaphylaxis,' even if you start to feel better -- symptoms can return, and further treatment is usually still needed.
• A second dose may be given after 5 to 15 minutes if symptoms have not improved or return, if a second auto-injector is available.
• Carry two auto-injectors with you if advised by your clinician, in case a second dose is needed or the first device fails.

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)

Missed dose

This medicine is used only for emergency treatment as needed, not on a regular schedule, so there is no missed dose to make up. Make sure your auto-injector has not expired and replace it before the expiry date so it is ready when needed.

Overdose

Seek emergency medical attention immediately if too much epinephrine is given or if severe symptoms occur, such as a very fast or irregular heartbeat, chest pain, severe headache, extremely high blood pressure, or difficulty breathing not related to the original allergic reaction. (1) (4)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Serious warnings

Interactions

• Beta-blocker medicines may reduce how well epinephrine works and can make some effects harder to reverse; emergency responders should still be told about beta-blocker use. (1) (4)
• Tricyclic antidepressants, MAO inhibitors, and thyroid hormone medicines may increase or prolong epinephrine's effects on heart rate and blood pressure. (2) (4)
• Other medicines such as digoxin (a cardiac glycoside), diuretics, and certain antihistamines may increase the risk of heart rhythm effects when combined with epinephrine. (1) (4)

Pregnancy, breastfeeding, kidney/liver function, age

Monitoring

Before starting

• Confirm the device has not expired and the solution is clear (not discoloured, cloudy, or containing particles)
• Confirm correct device strength for body weight (0.15 mg vs 0.3 mg)

During treatment

• After any use, continuous monitoring in an emergency medical setting for recurrence of symptoms (biphasic anaphylaxis can occur hours later)
• Heart rate and blood pressure monitoring, particularly in patients with known heart disease
• Assessment of the injection site for signs of accidental injection into the wrong location or early signs of infection

Storage

Store at room temperature, between about 20-25degC (68-77degF); avoid extreme heat or cold. Do not store in a vehicle's glove box or trunk, or in a refrigerator or freezer. Check the solution periodically through the viewing window and replace the device if it looks discoloured (pink or brown), cloudy, or contains particles, or once it reaches its expiry date.

Frequently asked questions

References

1. EPIPEN (epinephrine injection), for intramuscular or subcutaneous use -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · accessed 2026-07-31 · source 1
2. EpiPen Adrenaline (Epinephrine) 0.3 mg Auto-Injector -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Viatris Products Limited · United Kingdom · accessed 2026-07-31 · source 2
3. Adrenaline auto-injectors -- Article 31 referral, review startedEuropean Medicines Agency (EMA) -- Article 31 referral review · European Union · accessed 2026-07-31 · source 3
4. EpiPen (epinephrine injection USP) and EpiPen Jr -- Prescribing Information / Product MonographHealth Canada product monograph, Mylan Specialty L.P. (Viatris) · Canada · accessed 2026-07-31 · source 4
5. EPIPEN adrenaline (epinephrine) 0.3 mg/0.3 mL injection syringe auto-injector -- ARTG entry 42978 (and EPIPEN JR, ARTG entry 42980)Therapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-31 · source 5
6. EPIPEN -- New Zealand Data SheetMedsafe (New Zealand regulator) · New Zealand · accessed 2026-07-31 · source 6

Brand names by country

Single-ingredient epinephrine (adrenaline) names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries