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Auto-injector / IM adrenaline for anaphylaxis Pregnancy: A teratogenic effect has been demonstrated in animal studies; adrenaline crosses the placenta and there is some evidence of a slightly increased incidence of congenital abnormalities. Should only be used during pregnancy if the potential benefits outweigh the possible risks to the fetus. Parenteral adrenaline should not be used during the second stage of labour. Breast-feeding should be avoided in mothers receiving adrenaline injection.

Adrenaline (Anaphylaxis Protocol)

Brand names: EpiPen, Emerade, Jext, Auvi-Q

Used in: Epistaxis (Nosebleed)

This page concerns adrenaline (epinephrine) used under the anaphylaxis protocol, given by intramuscular injection into the anterolateral thigh as the immediate first-line treatment for anaphylaxis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 0.5 mg (0.5 ml of adrenaline 1 mg/ml (1:1000))
Route: Intramuscular — the best site is the anterolateral aspect of the middle third of the thigh, with a needle long enough to ensure injection into muscle. Do NOT give the 1 mg/ml (1:1000) solution intravenously. The subcutaneous route is not recommended for anaphylaxis as it is less effective
Frequency: If necessary, may be repeated several times at 5-minute intervals according to blood pressure, pulse and respiratory function
eMC (Adrenaline (Epinephrine) 1 mg/ml (1:1000) solution for injection, ampoule). To be administered by a trained healthcare professional. The IM route is recommended by the EU Resuscitation Council as the most appropriate for most individuals who have to give adrenaline to treat an anaphylactic reaction. Monitor the patient as soon as possible (pulse, blood pressure, ECG, pulse oximetry) to assess the response. Intravenous administration of adrenaline for anaphylaxis requires a 1:10,000 (0.1 mg/ml) solution — if the 0.1 mg/ml injection is not available, the 1 mg/ml (1:1000) solution must be diluted to 0.1 mg/ml before IV use; the IV route must be used with extreme caution and is best reserved for specialists familiar with IV adrenaline (generally more appropriate in the ICU or Emergency Department setting). Elderly: no specific dosage regime, but use with great caution as they may be more susceptible to cardiovascular side effects. PAEDIATRIC (SPC age bands, IM, 1 mg/ml (1:1000) solution): over 12 years — 0.5 mg (0.5 ml), or 0.3 mg (0.3 ml) if the child is small or pre-pubertal; 6–12 years — 0.3 mg (0.3 ml); 6 months–6 years — 0.15 mg (0.15 ml); under 6 months — 0.01 mg/kg (0.01 ml/kg). If necessary these doses may be repeated several times at 5–15 minute intervals according to blood pressure, pulse and respiratory function; a small volume syringe should be used. The SPC gives age bands rather than a single per-kg rule, so no structured per-kg paediatric dose is recorded here — verify paediatric dosing against a children's formulary.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients (contraindications are relative as the product is intended for use in life-threatening emergencies)
  • Do not use in fingers, toes, ears, nose, genitalia or buttocks owing to the risk of ischaemic tissue necrosis
  • Do not use if the solution is discoloured

Side effects

  • Palpitations and tachycardia; at high dosage or in sensitive patients, cardiac dysrhythmia (sinus tachycardia, ventricular fibrillation/cardiac arrest), acute angina attacks and risk of acute myocardial infarction
  • Pallor and coldness of the extremities; at high dosage, hypertension with risk of cerebral haemorrhage and vasoconstriction (cutaneous, extremities or kidneys)
  • Headache, tremors, dizziness, syncope; anxiety, nervousness, fear, hallucinations
  • Hyperglycaemia, hypokalaemia, metabolic acidosis
  • Dyspnoea, nausea, vomiting, sweating, weakness, mydriasis
  • Necrosis at the site of injection after repeated local injections

Interactions

  • Halothane and other halogenated anaesthetics — avoid adrenaline or use with extreme caution, in view of the risk of inducing ventricular fibrillation (UK SPC section 4.4)
  • Drugs antagonising the pressor effects: alpha-blockers (e.g. phentolamine), vasodilators such as nitrates, diuretics, antihypertensives, ergot alkaloids, phenothiazine antipsychotics (US labelling section 7.1)
  • Drugs potentiating the pressor effects: sympathomimetics, beta-blockers (e.g. propranolol), tricyclic antidepressants, MAO inhibitors, COMT inhibitors, clonidine, doxapram, oxytocin (US labelling section 7.2)
  • Drugs increasing arrhythmogenic potential: beta-blockers, cyclopropane and halogenated hydrocarbon anaesthetics, quinidine, antihistamines, exogenous thyroid hormones, diuretics, cardiac glycosides — observe for cardiac arrhythmias (US labelling section 7.3)
  • Potassium-depleting drugs (corticosteroids, diuretics, theophylline) potentiate the hypokalaemic effects (US labelling section 7.4)

Clinical monograph

How it works

By stimulating alpha-1 receptors it reverses vasodilation and reduces mucosal oedema, while beta-1 and beta-2 stimulation supports cardiac output and relieves bronchospasm, counteracting the core features of anaphylaxis.

Prescribing in practice

  • In anaphylaxis the route is intramuscular into the anterolateral thigh and must be given without delay; the much more concentrated cardiac-arrest intravenous strength must never be used for intramuscular anaphylaxis treatment.
  • Repeat the intramuscular dose after a short interval if there is no improvement, and escalate to senior/critical-care support with consideration of an intravenous infusion only by experienced clinicians.
  • Use a children's formulary for age- and weight-appropriate intramuscular dosing in paediatric anaphylaxis.

Monitoring

Monitor airway, breathing, circulation, oxygen saturation and ECG continuously, observing for biphasic reactions after initial recovery.

Counselling the patient

  • Adrenaline is the priority treatment; antihistamines and steroids are second-line and must not delay it.
  • Advise prolonged observation because symptoms can recur hours later.
  • Arrange auto-injector provision, training and allergy follow-up before discharge.

Evidence & guidelines

Intramuscular adrenaline is the cornerstone of anaphylaxis management in Resuscitation Council UK guidance and NICE guideline CG134.

Reference: Resuscitation Council UK Anaphylaxis Algorithm 2021; NICE CG134; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

📚 MRCEM Revision

Featured in these MRCEM clinical pathways

Adrenaline (Anaphylaxis Protocol) is a core drug in the following exam-focused workups on our sister siteReviseMRCEM.

MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.