An injection to raise low blood pressure during anaesthesia
Metaraminol
A hospital injection used to raise blood pressure that has dropped too low, often during anaesthesia.
What is Metaraminol?
Metaraminol is a hospital medicine given by injection or a drip into a vein to raise blood pressure that has fallen dangerously low, for example during an anaesthetic or in shock. It works by tightening blood vessels so the pressure within them rises. It is given only by trained staff with close monitoring, because raising blood pressure can cause the heart rate to slow as a reflex. If it leaks out of the vein it can damage the surrounding tissue, so the drip site is watched carefully.
Education and reference only. This is a plain-language guide to Metaraminol — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Metaraminol is a vasopressor, a medicine that raises blood pressure. It is used in hospital, usually by anaesthetists or intensive care and emergency teams, to bring blood pressure back up when it has dropped too low — for example during a spinal or general anaesthetic, or in certain types of shock. It is given as an injection or as a controlled drip into a vein, always with close monitoring of blood pressure and heart rate. It is a short-term, in-hospital treatment, not something used at home.
How it works
When blood pressure falls too low, not enough blood reaches the brain and other organs. Metaraminol acts on blood vessels to make them tighten, which increases the resistance the heart pumps against and raises blood pressure back towards a safe level. Because the body senses the higher pressure, it can respond by reflexively slowing the heart rate, which the team watches for. Its effect comes on quickly and wears off over a fairly short time, so the dose can be adjusted closely against the blood pressure readings.
Company & origin
Originated / developed by: Hospital manufacturers.
A hospital medicine used in the UK to raise dangerously low blood pressure, often during anaesthesia or in shock.
Practical use
How to take Metaraminol
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given in hospital by trained staff as an injection or a drip into a vein, never by yourself.
- Your blood pressure and heart rate are monitored continuously while it is being given.
- The drip site is checked carefully, because the medicine can damage tissue if it leaks out of the vein.
- The amount is adjusted closely against your blood pressure readings, as the effect comes on and wears off quickly.
- Tell the team about any heart, thyroid or diabetes problems, as it is used with extra care in these conditions.
Weighing it up
Advantages & disadvantages of Metaraminol
Advantages
- Quickly raises dangerously low blood pressure during anaesthesia or shock.
- Acts fast and wears off fairly quickly, so the dose can be fine-tuned against the readings.
- A well-established hospital medicine that trained teams are very familiar with.
Disadvantages
- Can cause the heart rate to slow as a reflex as blood pressure rises.
- Can damage tissue if it leaks out of the vein, so the drip site needs careful watching.
- Used only in hospital with continuous monitoring, not for use at home.
Practical use
Good to know
The most important thing to understand about metaraminol is that it is a powerful hospital medicine used only by trained staff with continuous monitoring of blood pressure and heart rate. A characteristic effect is that as it raises blood pressure, the heart rate can slow down as a reflex, which the team expects and watches for. A key safety point is that if it leaks out of the vein into the surrounding tissue, it can cause local tissue damage because it tightens small blood vessels, so the drip site is checked carefully and it is often given through a well-placed line. It is used with extra care in people with heart disease, an overactive thyroid or diabetes. Because it acts quickly and does not last long, the team can fine-tune it against the blood pressure readings minute by minute.
Who should not take it / use with caution
- People who have had a serious allergic reaction to metaraminol should not be given it.
- It is used with great care in people with heart disease, an overactive thyroid or diabetes.
- It is used cautiously alongside certain other medicines that affect blood pressure or heart rhythm.
Monitoring
- Continuous monitoring of blood pressure and heart rate while it is given.
- Careful checking of the drip site for any leak that could damage tissue.
- Adjusting the dose against the blood pressure readings throughout treatment.
Side effects
- A reflex slowing of the heart rate as blood pressure rises.
- Headache, a feeling of unease, or a rise in blood pressure that is too high if not adjusted.
- Tissue damage at the drip site if the medicine leaks out of the vein.
Key interactions
- It can interact dangerously with certain antidepressants known as MAOIs, raising blood pressure too much.
- Care is needed with other medicines that affect blood pressure or the heart's rhythm.
- Tell the team about all your medicines, as several can change how metaraminol behaves.
Available as: A solution for injection or drip into a vein, given in hospital.
Answers
Metaraminol: frequently asked questions
What is metaraminol used for?
It is a hospital medicine given into a vein to raise blood pressure that has dropped dangerously low, often during an anaesthetic or in shock.
Why does my heart rate slow down with it?
As metaraminol raises your blood pressure, the body can respond by reflexively slowing the heart rate; the team expects this and watches for it.
Why is the drip site watched so carefully?
If the medicine leaks out of the vein it can damage the surrounding tissue, so staff check the drip site closely and use a well-placed line.
Can I have it at home?
No. It is a powerful medicine given only in hospital by trained staff with continuous monitoring of blood pressure and heart rate.
How quickly does it work?
It acts quickly and wears off fairly quickly, which lets the team fine-tune the amount against your blood pressure readings.
Authoritative sources
- BNF
- NICE CKS
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