Pharmacology · Vasopressors and inotropes
Norepinephrine !
Noradrenaline: the usual first vasopressor in septic shock. It tightens blood vessels to restore blood pressure and is infused through a large or central vein.
Updated 2026-11-01
Also called: Noradrenaline
The figure shows noradrenaline bound to the human alpha-1A adrenergic receptor in complex with a G protein.
Mechanism of action
Norepinephrine, the sympathetic neurotransmitter, is a strong alpha-1 agonist with beta-1 activity and little beta-2 effect. Alpha-1 stimulation constricts arterioles and veins, raising peripheral resistance and venous return; beta-1 supports contractility. The rise in pressure triggers a reflex slowing of the heart, so cardiac output changes little.
- Norepinephrine binds vascular alpha-1 receptors
- Gq raises calcium and constricts arterioles and veins
- Peripheral resistance and blood pressure rise
- Beta-1 supports contraction; reflex bradycardia can follow
Pharmacokinetics
- Distribution
- Localises mainly in sympathetic nervous tissue; poor oral bioavailability
- Metabolism
- COMT and MAO in the liver and other tissues; metabolites include normetanephrine and vanillylmandelic acid
- Half-life
- About 2.4 minutes (label)
- Onset and duration
- Steady state within about 5 minutes of starting the infusion (label)
Indications
- Severe acute hypotension, including septic shock Sepsis and septic shock →
- Vasodilatory shock after correction of volume
Adverse effects
Common
- Hypertension and reflex bradycardia
- Headache and anxiety
- Breathing difficulty
- Ischaemic injury at the infusion site
Contraindications
- Uncorrected hypovolaemia (relative: volume is restored first)
- Use in the leg veins of older people or people with occlusive vascular disease is avoided
Key interactions
- MAO inhibitors, including linezolid
- Severe, prolonged hypertension
- Tricyclic antidepressants
- Severe, prolonged hypertension
- Halogenated anaesthetics
- Ventricular tachycardia or fibrillation
- Antidiabetic drugs
- Norepinephrine lowers insulin sensitivity and raises glucose
What is monitored
- Continuous, preferably invasive, blood pressure
- Heart rate and rhythm
- Urine output, lactate and peripheral perfusion
- Blood glucose
- Infusion site for extravasation
Administration and safety
- Diluted before use, preferably in a dextrose-containing solution, which reduces oxidation; given by infusion pump.
- Infuse into a large vein, preferably central; avoid leg veins and catheter tie-in techniques.
- Do not use the solution if it is pinkish, darker than slightly yellow or has a precipitate.
- If it extravasates: stop the infusion at that site and infiltrate phentolamine as early as possible.
- Blood or plasma, if needed, is given through a separate line.
Nursing care
- Before: hypovolaemia is corrected; if the response is poor, think of hidden hypovolaemia.
- During: blood pressure very often until stable (an arterial line is common), then regularly; ECG.
- Check the infusion site and the colour and temperature of the limbs; report blanching along the vein.
- Wean gradually; avoid abrupt stopping.
Pregnancy and breastfeeding
Small studies at delivery have not shown a higher risk of birth defects or adverse outcomes; untreated shock is fatal for mother and fetus.
Test yourself
Think of the answer, then tap the question to see it.
Why does norepinephrine often slow the heart even though it stimulates beta-1 receptors?
The marked rise in blood pressure from alpha-1 vasoconstriction activates the baroreflex, and vagal slowing outweighs the direct beta-1 effect.
Which antibiotic, an MAO inhibitor, can cause a hypertensive reaction with norepinephrine?
Linezolid, which has MAO-inhibiting activity.
What is the main danger of starting norepinephrine in uncorrected hypovolaemia?
Severe peripheral and visceral vasoconstriction with low renal flow, tissue hypoxia and lactic acidosis despite a 'normal' pressure.
What should the nurse do if the skin along the infused vein blanches or the line extravasates?
Stop the infusion at that site, change the site, and arrange prompt local infiltration of phentolamine to prevent necrosis.
Related drugs
Related conditions
← Back to the class: 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 - NOREPINEPHRINE BITARTRATE injection, solution, concentrate (DailyMed (U.S. National Library of Medicine), 2022); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Farmacología básica y clínica (Katzung), cap. 9 (McGraw Hill, 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.