[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/) › Epinephrine

[Pharmacology](https://durgical.com/en/pharmacology/) · [Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/)

# Epinephrine

Adrenaline: the first medicine for anaphylaxis, given into the thigh muscle. By infusion it also supports blood pressure in septic shock.

Updated 2026-11-01

- Class: [Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/)
- Receptor: Alpha and beta adrenergic receptors (beta-2 shown)
- ATC code: C01CA24
- WHO Model List of Essential Medicines

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

Also called: Adrenaline

◎**Alpha and beta adrenergic receptors (beta-2 shown)**Epinephrine

ⓘ The figure shows epinephrine bound to the human beta-2 adrenergic receptor, stabilised by a nanobody in the active state.

**Target in 3D:** Alpha and beta adrenergic receptors (beta-2 shown). PDB structure 4LDO (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/4LDO) · Drag to rotate · pinch to zoom

## Mechanism of action

Epinephrine stimulates alpha and beta receptors. Alpha-1 constricts vessels and reduces mucosal oedema; beta-1 increases the force and rate of the heartbeat; beta-2 relaxes bronchial smooth muscle and reduces the release of mediators from mast cells. In anaphylaxis these actions reverse hypotension, airway swelling and bronchospasm together.

- Epinephrine activates alpha and beta adrenergic receptors
- Alpha-1: vasoconstriction and less mucosal oedema
- Beta-1: stronger, faster heartbeat
- Beta-2: bronchodilation and fewer mast-cell mediators

## Pharmacokinetics

**Absorption**
Intramuscular injection into the thigh is absorbed quickly; poor oral bioavailability

**Metabolism**
Rapidly inactivated by COMT and MAO

**Half-life**
Effective half-life under 5 minutes after intravenous use (label)

**Onset and duration**
Fast; a steady state is reached soon after an infusion starts

## Indications

- Anaphylaxis and other severe type I allergic reactions [Anaphylaxis →](https://durgical.com/en/conditions/anaphylaxis/)
- Hypotension in septic shock (infusion) [Sepsis and septic shock →](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- Cardiac arrest (resuscitation protocols)

## Adverse effects

### Common

- Anxiety, restlessness and tremor
- Palpitations and tachycardia
- Pallor, sweating and headache
- Nausea and vomiting
- Hyperglycaemia and raised lactate

### Serious (rare, important)

- Ventricular arrhythmias and myocardial ischaemia
- Severe hypertension with risk of cerebral haemorrhage
- Pulmonary oedema
- Tissue necrosis after extravasation or injection into fingers, hands or feet

## Contraindications

- None absolute in anaphylaxis: the label lists no contraindications

## Key interactions

**Beta blockers (for example propranolol)**
Listed among drugs that potentiate epinephrine and raise the risk of arrhythmias; with non-selective blockers the alpha effect acts unopposed

**MAO inhibitors and tricyclic antidepressants**
Severe, prolonged hypertension

**Halogenated anaesthetics, digoxin and diuretics**
Higher risk of arrhythmias

**Alpha blockers, nitrates and other vasodilators**
Weaker pressor effect

## What is monitored

- Blood pressure, heart rate and rhythm
- Respiratory status and oxygen saturation in anaphylaxis
- Glucose and lactate during infusions

## Administration and safety

- Anaphylaxis: intramuscular injection into the anterolateral thigh, through clothing if needed; not into the buttock, fingers, hands or feet.
- Epinephrine comes in several strengths and forms for intramuscular or intravenous use: check the label and route carefully before giving it.
- Infusions: diluted, by pump, preferably through a central or large vein; check the site often for blanching or extravasation.
- Do not use the solution if it is coloured, cloudy or has particles.
- Epinephrine and ephedrine have look-alike names: read the label twice.

## Nursing care

- In anaphylaxis, epinephrine is not delayed: it is the first-line medicine, and antihistamines do not replace it.
- Monitor blood pressure, heart rate, breathing and oxygen saturation; symptoms can return after the first response.
- During infusions, watch ECG, glucose and the infusion site; wean gradually.
- Teaching: people with prescribed auto-injectors learn when and how to use them and to seek emergency care afterwards.

## Pregnancy and breastfeeding

Anaphylaxis and septic shock threaten mother and fetus, so epinephrine is used when needed; it can constrict uterine vessels and reduce uterine blood flow.

## Memory aid

Anaphylaxis: Adrenaline in the Anterolateral thigh, As soon As possible.

## Test yourself

Think of the answer, then tap the question to see it.

## Which receptor actions of epinephrine reverse the main features of anaphylaxis?

Alpha-1 vasoconstriction (hypotension, oedema), beta-1 cardiac stimulation and beta-2 bronchodilation with less mast-cell mediator release.

## Where is epinephrine injected in anaphylaxis, and where is it avoided?

Into the anterolateral thigh muscle. The buttock, fingers, hands and feet are avoided because of poor absorption, infection or ischaemic necrosis.

## What can happen to the pressure of a patient on a non-selective beta blocker who receives epinephrine?

With beta-2 vasodilation blocked, the alpha-1 vasoconstriction acts unopposed and blood pressure can rise sharply; arrhythmias are also more likely.

## Which metabolic changes does an epinephrine infusion cause?

Hyperglycaemia (glycogenolysis, less insulin release) and a rise in blood lactate.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/epinephrine/)

## Related drugs

- [Norepinephrine](https://durgical.com/en/pharmacology/norepinephrine/)
- [Dopamine](https://durgical.com/en/pharmacology/dopamine/)
- [Isoprenaline](https://durgical.com/en/pharmacology/isoprenaline/)
- [Phentolamine](https://durgical.com/en/pharmacology/phentolamine/)

## Related conditions

- [Anaphylaxis](https://durgical.com/en/conditions/anaphylaxis/)
- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)

[← Back to the class: Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - EPINEPHRINE injection](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=577f987e-d3af-4f49-ab44-5db9cbf46601) (DailyMed (U.S. National Library of Medicine), 2026); [Epinephrine Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a603002.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C01CA24) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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