An EpiPen is an epinephrine auto-injector, the emergency treatment for anaphylaxis. This guide combines our EpiPen and epinephrine pages. It covers when to use epinephrine, how to give it, auto-injectors versus the needle-free nasal spray, why to carry two, side effects, and how to store and replace your device.
It draws on MedlinePlus, the U.S. Food and Drug Administration (FDA) and the American College of Allergy, Asthma and Immunology (ACAAI). It is general information, not medical advice. In an emergency, call 911.
Key takeaways
- Epinephrine is the first-line treatment for anaphylaxis, and antihistamines are not a substitute (ACAAI).
- Use it at the first sign of a serious reaction. If you are not sure, use it (ACAAI).
- Inject into the middle of the outer thigh, through clothing if needed, and get emergency care (MedlinePlus).
- Carry two devices. Only a healthcare provider should give more than two doses in one episode (MedlinePlus).
- A needle-free nasal spray, neffy, is approved for adults and for children 4 and older who weigh at least 15 kg (FDA).
What epinephrine does
Epinephrine (also called adrenaline) is the first-line treatment for anaphylaxis, a sudden, life-threatening allergic reaction (ACAAI). It relaxes the muscles in the airways and tightens blood vessels, which helps open the airways and raise dangerously low blood pressure (MedlinePlus). It is used with emergency medical care for severe reactions to foods, insect stings, medicines, latex and other triggers (MedlinePlus).
It is not a treatment for everyday seasonal allergy symptoms like sneezing or itchy eyes. Those are treated with medicines such as antihistamines, nasal steroid sprays and decongestants. Antihistamines are not a substitute for epinephrine in a severe reaction (ACAAI).
When to use an EpiPen
Use epinephrine at the first sign of a serious allergic reaction, as your doctor prescribed (MedlinePlus). If you are not sure whether a reaction needs epinephrine, the ACAAI advises using it right away, because the benefits far outweigh the risk of an unneeded dose. A delay in using epinephrine is common in deaths from severe food reactions (ACAAI). Use it immediately for severe symptoms such as (ACAAI):
- Generalized hives
- Repetitive coughing
- Shortness of breath or trouble breathing
- Symptoms in more than one part of the body, such as hives or swelling with vomiting, diarrhea or abdominal pain
- Tightness in the throat or trouble swallowing
- Weak pulse
Between 10 and 20 percent of life-threatening allergic reactions have no skin symptoms, so don’t wait for hives (ACAAI). Your allergist should give you a written emergency plan that says which medicines to use and when (ACAAI). See also our allergy emergency guide.
How to use an epinephrine auto-injector
Every device works a little differently, so read the instructions that came with yours and practice with a trainer device if you have one. The general steps are:
- Take the auto-injector out of its carrying case and remove the safety cap, following the device instructions (MedlinePlus).
- Press it firmly into the middle of the outer thigh. It can go through clothing in an emergency (MedlinePlus).
- Hold it in place for the time on the label. Depending on the brand, that is 2 to 10 seconds (ACAAI).
- Get emergency medical care right away, as MedlinePlus advises, and take the used device with you (MedlinePlus). The ACAAI notes that 2023 guidelines suggest making a personal plan with your allergist for what to do after a dose (ACAAI).
- If symptoms continue or come back, use a second dose with a new device if your doctor told you to. Only a healthcare provider should give more than two doses for one episode (MedlinePlus).
Auto-injector or nasal spray?
Epinephrine now comes as an auto-injector or a nasal spray (ACAAI). Your doctor chooses the device and strength, often based on body weight.
| Auto-injector | Nasal spray (neffy) | |
|---|---|---|
| How it is given | Into the middle of the outer thigh, through clothing if needed | One spray into one nostril |
| Who it is for | Adults and children; the strength depends on weight | 2 mg for people who weigh at least 30 kg (66 lb); 1 mg for children 4 and older who weigh 15 to under 30 kg (33 to 66 lb) |
| Second dose | A new device if symptoms continue or return, as your doctor advises | A new device in the same nostril, starting 5 minutes after the first if symptoms don’t improve or get worse |
| Examples | Auvi-Q, EpiPen, EpiPen Jr and generic versions | neffy (FDA-approved in 2024 for adults, and in 2025 for younger children) |
The FDA approved neffy in August 2024 as the first needle-free epinephrine for anaphylaxis (FDA), then approved a 1 mg dose for children in March 2025 (FDA).
Why carry two doses
One dose may not be enough, and symptoms can return. Keep two devices with you at all times (MedlinePlus). The ACAAI advises a second dose if symptoms don’t improve or come back (ACAAI).
Side effects
Common side effects include anxiety, restlessness, dizziness and shakiness. Rarely, epinephrine can cause an abnormal heart rhythm, a sharp rise in blood pressure or other serious effects, so people with some health conditions should ask their allergist when to use it (ACAAI). MedlinePlus also lists (MedlinePlus):
- Dizziness or weakness
- Headache
- Nausea or vomiting
- Nervousness, anxiety or restlessness
- Pale skin or sweating
- Pounding, fast or irregular heartbeat
- Redness, swelling, warmth or tenderness where it was injected
- Shaking
Tell the emergency team about any side effects. For an overdose, call Poison Control at 1-800-222-1222, or 911 if the person has collapsed, had a seizure, has trouble breathing or can’t be woken up (MedlinePlus).
Storage, expiry and disposal
- Check the expiration date and look at the liquid from time to time. Replace it if it is expired, discolored or has particles (MedlinePlus).
- Don’t put used or expired devices in the trash. Take a used one to the emergency room, or ask your pharmacist about a take-back program (MedlinePlus).
- If a device is dropped, check that it isn’t broken or leaking (MedlinePlus).
- If an expired device is the only one you have in an emergency, use it anyway (ACAAI).
- Keep the device in its carrying tube at room temperature, away from light, heat and moisture. Don’t refrigerate it or leave it in a car (MedlinePlus).
Who should carry epinephrine
Allergists advise that everyone with a food allergy carry epinephrine, especially people who have had anaphylaxis before, have both a food allergy and asthma, or are allergic to peanuts, tree nuts, fish or shellfish (ACAAI). An allergist can confirm triggers with allergy testing. For sting allergies, venom immunotherapy is 90 to 98 percent effective at preventing future reactions (ACAAI). For children, see our children’s allergy guide and back-to-school allergy guide.
In hospitals, doctors also use epinephrine for other emergencies, such as low blood pressure from septic shock (MedlinePlus).
Frequently asked questions
Is epinephrine used for seasonal allergies?
No. Epinephrine treats anaphylaxis. Everyday seasonal symptoms are treated with antihistamines, nasal steroids and other medicines (MedlinePlus). See the differences between life-threatening and seasonal allergies.
Can I take an antihistamine instead?
No. Antihistamines don’t replace epinephrine in a severe reaction (ACAAI).
Can I use an expired EpiPen?
Replace expired devices. But if an expired one is all you have in an emergency, use it (ACAAI).
Do I need the ER after using it?
MedlinePlus advises getting emergency medical care right after using epinephrine (MedlinePlus). The ACAAI says care is sometimes needed and suggests a personal plan with your allergist, based on 2023 guidelines (ACAAI). If you don’t have a plan, call 911.
Is there an option without a needle?
Yes. The neffy nasal spray is FDA-approved for adults and children who weigh at least 15 kg (33 lb) (FDA).
Related reading
Local pollen and allergist guides
Pollen seasons and triggers change by city. See what is in the air near me and where to find an allergist.
City pollen guides
State guides
Sources
Originally written by Madiha Ather Hashmi (2020) and merged with our epinephrine guide. Updated November 2026 with current sources.
This page is for general information only and is not medical advice. Talk with your doctor or pharmacist about your symptoms and before starting, stopping or combining any medicine.