Epinephrine: Anaphylaxis & Arrest

Why this matters

Epinephrine is one drug name with more than one job. Anaphylaxis needs an intramuscular injection in the mid-anterolateral thigh. Cardiac arrest needs intravenous or intraosseous epinephrine on a timed cycle. The vials can look alike. The concentration on the label is not the dose.

Concentration is the strength printed on the vial, in milligrams per milliliter. Dose is the amount your protocol card tells you to give, by a named route. Your protocol sets the dose. This site does not. Never swap the anaphylaxis vial and the arrest vial. Never give the intramuscular concentration by intravenous push.

Clinical sequence

1. Name the job before you open the pouch. Say anaphylaxis, intramuscular, or arrest, intravenous or intraosseous. That one sentence prevents many mix-ups.
2. Read the vial. Current U.S. labels use mg/mL. Old ratio language, such as 1:1,000 or 1:10,000, is retired. Confirm the concentration in your hand matches the indication you just named.
3. Anaphylaxis: give it intramuscularly in the mid-anterolateral thigh, the vastus lateralis, per protocol. Do not wait for an IV, a full-body rash, or diphenhydramine. Then work on the airway and fluids.
4. Arrest: CPR first. Epinephrine follows the arrest cycle by the intravenous or intraosseous route, per protocol. That is a different concentration from the intramuscular anaphylaxis vial. Do not push the intramuscular concentration into a vein.
5. Have a partner check an intravenous or intraosseous dose when you can. The wrong vial is a deadly mix-up. If you were interrupted, start again at the label.

Two Big Contexts

Anaphylaxis

• Usually intramuscular in the mid-anterolateral thigh, early. The deltoid is not the first choice in standard teaching.
• The concentration and the dose come from your protocol or the auto-injector instructions. Read that packaging every time.
• You may repeat the dose if the patient stays sick and the protocol allows it. Refractory anaphylaxis is more epinephrine and an airway plan, not more antihistamine.

Cardiac arrest

• Intravenous or intraosseous, on a timed cycle, in the usual advanced-life-support framework. Follow your protocol exactly.
• Many systems stock a different preparation from the intramuscular anaphylaxis vial. Do not choose it without reading the label.

Some systems also use push-dose or infusion epinephrine for shock. Use that only if you are trained and authorized. See the push-dose lesson.

Safety Habits

• Say the indication, the concentration, the route, and the volume before it goes in.
• Never grab epinephrine without reading the vial.
• Know your stock in mg/mL. Read the label. Do not rely on old ratio memory.
• 1 mg/mL and 0.1 mg/mL are concentration labels, not a dose order. The 1 mg/mL label is the usual intramuscular anaphylaxis vial. The 0.1 mg/mL label is the usual arrest intravenous or intraosseous vial. Verify what you carry. Never give the 1 mg/mL concentration by intravenous push.
• Document the time and the route. The next crew and the emergency department need that.

Key points

• Anaphylaxis epinephrine is an intramuscular dose in the mid-anterolateral thigh, not the arrest concentration. Do not delay it for IV access. Never give that intramuscular concentration by intravenous push.
• Arrest: high-quality CPR remains the foundation. Epinephrine timing follows the protocol, by the intravenous or intraosseous route, often from a different concentration.
• This site does not publish operational doses. Your protocol is the authority.

Common errors

• Giving the intramuscular concentration by intravenous push, or giving the arrest concentration into the muscle, without reading the label.
• Using epinephrine for bleeding shock with no protocol indication.
• Skipping the time and the route in the documentation.

Practice

Related: Anaphylaxis recognition, Dosing safety.

Sources & Further Study

Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.

• NASEMSO National Model EMS Clinical Guidelines (2022) — U.S. EMS model language. Your protocol still decides.
• AAAAI/ACAAI Anaphylaxis Practice Parameter (2023) — Intramuscular injection in the mid-anterolateral thigh.
• AHA 2025 Part 9: Adult Advanced Life Support — Arrest epinephrine is intravenous or intraosseous on a timed cycle, not the anaphylaxis intramuscular pathway.
• Current labels use mg/mL, such as 1 mg/mL versus 0.1 mg/mL, not ratio expressions such as 1:1,000. Those are concentration labels, not a dose order. Read the vial every time.
• Your anaphylaxis protocol and your cardiac-arrest protocol.