A calcium-channel blocker for brain blood vessels
Nimodipine
A calcium-channel blocker used to prevent spasm of brain arteries after a bleed around the brain.
What is Nimodipine?
Nimodipine is a calcium-channel blocker that acts mainly on the blood vessels in the brain. It is used in hospital to help prevent dangerous narrowing (spasm) of brain arteries after a subarachnoid haemorrhage, a type of bleed around the brain. It is taken regularly under close supervision, can lower blood pressure, and interacts with grapefruit.
Education and reference only. This is a plain-language guide to Nimodipine — 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
Nimodipine is a dihydropyridine calcium-channel blocker that is unusual in acting particularly on the arteries supplying the brain. In the UK it is used specifically to prevent and treat the brain-artery narrowing (cerebral vasospasm) that can follow a subarachnoid haemorrhage, a bleed in the space around the brain. It is given in a hospital setting and is not used as a routine blood-pressure medicine.
How it works
After a subarachnoid haemorrhage, the arteries in the brain can go into spasm and narrow, cutting blood flow and risking further damage. Nimodipine blocks calcium entry into the muscle of these vessel walls, helping to keep the brain arteries relaxed and open so blood can keep flowing. This reduces the harm caused by vasospasm.
Company & origin
Originated / developed by: Developed by Bayer; also available as a generic medicine..
Developed by Bayer in Germany and used to protect the brain after a particular type of brain haemorrhage.
Practical use
How to take Nimodipine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is taken regularly at evenly spaced times, often around the clock, under hospital supervision.
- Swallow tablets whole with water and avoid grapefruit or grapefruit juice.
- It must only be given by the route your team intends; certain wrong routes can cause serious harm.
- Keep to the schedule and do not skip doses, as steady levels protect the brain arteries.
- Your blood pressure is checked regularly because the medicine can lower it.
- Report dizziness, faintness or a fast heartbeat to the staff caring for you.
Weighing it up
Advantages & disadvantages of Nimodipine
Advantages
- Acts particularly on brain arteries, helping prevent the vasospasm that can follow a brain bleed.
- Can reduce the risk of further brain injury after subarachnoid haemorrhage.
- Has a well-defined, evidence-based role in this specific emergency.
Disadvantages
- Can lower blood pressure too much, which itself can be harmful after a brain bleed.
- Must be given by the correct route only; some wrong routes are dangerous, so it needs careful handling.
- Interacts with grapefruit and several medicines, and is only for this specialist situation rather than general use.
Practical use
Good to know
Nimodipine is started promptly and taken regularly around the clock to keep brain arteries protected, so doses should not be skipped. It can lower blood pressure, so this is watched closely. It must only be given by the correct route under medical supervision; giving it the wrong way can be very dangerous. Avoid grapefruit and grapefruit juice.
Who should not take it / use with caution
- People with very low blood pressure or unstable circulation, unless managed by the specialist team.
- People with severe liver disease, who may need it avoided or adjusted.
- People taking certain medicines that strongly affect its blood levels, without specialist review.
Monitoring
- Blood pressure and pulse, often very closely after a brain haemorrhage.
- Neurological condition and signs of brain-artery spasm.
- Liver function where relevant.
Side effects
- Low blood pressure, dizziness or faintness.
- Flushing, headache and a fast or pounding heartbeat.
- Nausea and feeling generally unwell.
- Swollen ankles in some people.
Key interactions
- Grapefruit and grapefruit juice, which raise its blood levels.
- Other blood-pressure-lowering medicines, which add to the effect.
- Some antifungals, antibiotics and epilepsy medicines that change how it is broken down.
Available as: Available as tablets and as a solution given by the specialist team in hospital.
Answers
Nimodipine: frequently asked questions
Why is nimodipine used after a brain bleed?
After a subarachnoid haemorrhage the brain arteries can narrow and reduce blood flow. Nimodipine helps keep these vessels open, lowering the risk of further brain injury.
Why must doses not be skipped?
Steady levels of the medicine give continuous protection to the brain arteries, so it is taken on a regular, evenly spaced schedule and missed doses are avoided.
Is it the same as blood-pressure tablets?
It is in the same family as some blood-pressure medicines, but it acts mainly on brain arteries and is used for this specific emergency rather than for everyday high blood pressure.
Can I have grapefruit while taking it?
No. Grapefruit and its juice can raise the level of nimodipine in your blood and increase side effects, so they should be avoided.
Why does it need such careful handling?
Nimodipine must only be given by the route your team intends. Giving it by certain wrong routes can be very dangerous, which is why it is supervised in hospital.
The wider class
About Calcium-channel blockers
Nimodipine belongs to the calcium-channel blockers class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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