Sympathomimetic Vasopressor Pregnancy: Animal studies have shown a teratogenic effect; limited epidemiological data appear to indicate no particular malformation effect. Ephedrine crosses the placenta and has been associated with an increase in foetal heart rate and beat-to-beat variability, so it should be avoided or used with caution and only if necessary during pregnancy. It is excreted in breast milk (irritability and disturbed sleep reported in breast-fed infants); either avoid ephedrine or suspend lactation for 2 days following administration.

Ephedrine (IV — Anaesthesia)

Brand names: Ephedrine

Intravenous ephedrine is a sympathomimetic agent used in anaesthesia to treat hypotension, particularly that associated with spinal or epidural anaesthesia.

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: 3 to 6 mg by slow intravenous injection (maximum 9 mg per injection)

Route: Intravenous — slow intravenous injection. Ephedrine must be used solely by or under the supervision of the anaesthetist. Source product: Ephedrine Hydrochloride 3 mg/ml Solution for Injection in Pre-filled Syringe. Check that the solution is clear and contains no visible particles before administration.

Frequency: Repeated as needed every 3-4 minutes

Max: Maximum 9 mg per injection; maximum 30 mg per episode — a lack of efficacy after 30 mg should lead to reconsideration of the choice of therapeutic agent. The dose administered in 24 hours must not exceed 150 mg.

SALT AND STRENGTH: the extracted dose is for ephedrine HYDROCHLORIDE 3 mg/ml pre-filled syringe (UK SPC) — check the salt and the concentration of the presentation in use before dosing. PAEDIATRIC: this product is generally NOT recommended for use in children because of insufficient data on efficacy, safety and dosage; in children under 12 years safety and efficacy have not been established and no data are available; in children over 12 years the posology and method of administration are the same as for adults. No per-kg paediatric dose is stated — verify against a children's formulary. ELDERLY: as for adults. RENAL/HEPATIC: no dose adjustment is recommended. EXCIPIENT: contains 33.9 mg sodium per 10 ml pre-filled syringe (1.7% of the WHO recommended maximum daily intake of 2 g sodium for an adult). ANTI-DOPING: athletes should be informed that this preparation contains an active substance which might give a positive reaction in anti-doping tests. US CROSS-CHECK — DIFFERENT SALT, DO NOT INTERCHANGE MG-FOR-MG: the openFDA record in this bundle is ephedrine SULFATE injection 50 mg/mL (equivalent to 38 mg/mL of ephedrine base), which must be diluted before intravenous bolus administration; it recommends an initial dose of 5 to 10 mg by intravenous bolus for clinically important hypotension in the setting of anaesthesia, with additional boluses as needed not exceeding a total dosage of 50 mg, titrated to the blood pressure goal. Those US figures are NOT the values extracted above.

Dose adjustments

Renal

No dose adjustment is recommended for patients with renal or hepatic impairment.

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
In combination with other indirect sympathomimetic agents such as phenylpropanolamine, phenylephrine, pseudoephedrine and methylphenidate
In combination with alpha sympathomimetic agents
In combination with non-selective MAO inhibitors, or within 14 days of their withdrawal

Side effects

Cardiac (common): palpitations, hypertension, tachycardia; rare cardiac arrhythmia; not known — anginal pain, reflex bradycardia, cardiac arrest, hypotension
Nervous system (common): nervousness, irritability, restlessness, weakness, insomnia, headache, sweating
Psychiatric (common): confusion, anxiety, depression; not known — psychotic states, fear
Gastrointestinal (common): nausea, vomiting; respiratory (common): dyspnoea; not known — pulmonary oedema
Rare: acute urinary retention; not known — hypokalaemia, changes in blood glucose levels, cerebral haemorrhage, episodes of angle-closure glaucoma, hypersensitivity

Interactions

Indirect sympathomimetic agents (phenylpropanolamine, pseudoephedrine, phenylephrine, methylphenidate) — contraindicated combination; risk of vasoconstriction and/or acute episodes of hypertension (section 4.5)
Alpha sympathomimetics (oral and/or nasal route) — contraindicated combination (section 4.5)
Monoamine oxidase inhibitors — many sympathomimetics interact with MAOIs; do not give to patients receiving them or within 14 days of termination; avoid sympathomimetics with selective MAO inhibitors (section 4.4)
Halogenated anaesthetics (cyclopropane, halothane and others) — avoid or use with caution, as they may induce ventricular fibrillation (section 4.4)
Cardiac glycosides, quinidine or tricyclic antidepressants — increased risk of arrhythmia; antihypertensive therapy — ephedrine increases blood pressure, so special care is advised (section 4.4)

Clinical monograph

How it works

It has mixed action, directly stimulating alpha and beta adrenoceptors and indirectly releasing noradrenaline, raising blood pressure, heart rate and cardiac output.

Prescribing in practice

It should be given by titrated increments with continuous blood pressure monitoring, as it can cause hypertension, tachycardia and arrhythmias, especially with excessive dosing.
Tachyphylaxis can develop with repeated dosing, so a vasopressor with a different mechanism may be needed if the response diminishes.
It can interact dangerously with monoamine oxidase inhibitors, producing a hypertensive crisis, and should be used cautiously in cardiovascular disease and hyperthyroidism.

Monitoring

Monitor blood pressure, heart rate and ECG continuously during and after administration.

Counselling the patient

Inform the team that the patient may experience a transient rise in heart rate and blood pressure.
Check for current or recent monoamine oxidase inhibitor use before giving.

Evidence & guidelines

Its use for anaesthesia-related hypotension reflects long-standing established practice and product information.

Reference: OAA (Obstetric Anaesthetists Association) Guidelines; NICE NG121 (Caesarean Section); 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways