A blood pressure medicine used in pregnancy
Methyldopa
A centrally-acting blood pressure medicine, particularly favoured in pregnancy.
What is Methyldopa?
Methyldopa is a blood pressure medicine that works mainly in the brain to calm the signals that tighten blood vessels, lowering blood pressure. It is the medicine most often chosen to treat high blood pressure in pregnancy because it has been used safely for many years and is well studied. Its main drawbacks are drowsiness, tiredness and a low mood, especially when starting. Rarely it can affect the liver or the blood, so occasional blood tests are usual.
Education and reference only. This is a plain-language guide to Methyldopa — 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
Methyldopa is a centrally-acting medicine for high blood pressure, meaning it acts mostly in the brain rather than directly on the blood vessels. It has been used for decades and is now best known as the preferred choice for treating high blood pressure during pregnancy, where its long track record is reassuring. It is taken by mouth as a tablet, usually more than once a day. It is less used for general high blood pressure today because newer medicines often cause fewer side effects.
How it works
Methyldopa is changed in the body into a substance that acts in the brain to reduce the nerve signals that tighten blood vessels and speed the heart. With those signals quietened, the blood vessels relax and blood pressure falls. Because it works through the brain, it commonly causes drowsiness and tiredness, particularly in the first days or weeks until the body adjusts.
Company & origin
Originated / developed by: Generic (long-established).
A long-established blood pressure medicine, used in the UK especially during pregnancy because of its well-known safety record.
What it treats
Conditions Methyldopa is used for
Practical use
How to take Methyldopa
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it regularly as prescribed, usually two or three times a day, at about the same times.
- Expect drowsiness when you first start; do not drive or use machines until you know how it affects you.
- Get up slowly from sitting or lying down, as it can make you feel faint when you stand.
- Tell your prescriber if you feel persistently low in mood or notice yellowing of the skin or eyes.
- Do not stop taking it suddenly; if it needs to be stopped, this should be done gradually on advice.
- Keep your blood-test appointments, as these check your liver and blood while you take it.
Weighing it up
Advantages & disadvantages of Methyldopa
Advantages
- The best-established and usually preferred blood pressure medicine for use in pregnancy.
- Has a very long safety record and is well studied in mothers and babies.
- Effective at lowering blood pressure when taken regularly.
Disadvantages
- Commonly causes drowsiness, tiredness and sometimes a low mood, especially at first.
- Needs to be taken more than once a day, unlike some newer medicines.
- Can rarely affect the liver or the blood, so blood tests are needed.
Practical use
Good to know
Methyldopa is widely trusted in pregnancy because there is long experience showing it is safe for mother and baby, which is why it is often the first choice then. Drowsiness, tiredness and feeling slightly low in mood are common at the start and usually ease, but a more lasting low mood or depression should be reported. It can occasionally affect the liver or cause a change in the blood that breaks down red cells, so blood tests are usually done in the early weeks and from time to time afterwards. It may make you feel faint when you stand up quickly, and it should not be stopped suddenly without advice.
Who should not take it / use with caution
- People with active liver disease or a history of liver problems caused by methyldopa should not take it.
- It is generally avoided in people with current depression, as it can worsen mood.
- People with certain blood disorders affecting red cells should use it only on specialist advice.
Monitoring
- Blood pressure checks to confirm it is well controlled.
- Blood tests for the liver and blood count, especially in the first weeks.
- Reviewing mood and drowsiness, particularly when starting or increasing the dose.
Side effects
- Drowsiness, tiredness, a dry mouth and feeling faint on standing are common, especially early on.
- Low mood or depression in some people, which should be reported.
- Rarely, liver problems or a change in the blood that breaks down red cells.
Key interactions
- Adds to the blood-pressure-lowering and drowsy effects of other blood pressure medicines and sedatives.
- Iron supplements can reduce how much methyldopa is absorbed, so separate the timing.
- Can interact with some medicines for Parkinson's and certain antidepressants, so tell your prescriber what you take.
Available as: Tablets taken by mouth.
Answers
Methyldopa: frequently asked questions
Why is methyldopa used in pregnancy?
It has been used safely for many years with a great deal of experience in mothers and babies, which is why it is often the first choice for high blood pressure in pregnancy.
Will it make me sleepy?
Drowsiness and tiredness are common when you first start and usually ease; avoid driving until you know how it affects you.
Can it affect my mood?
It can cause low mood or, rarely, depression, so tell your prescriber if you feel persistently low while taking it.
Why do I need blood tests?
Methyldopa can occasionally affect the liver or the blood, so blood tests in the early weeks and from time to time afterwards help catch any problem early.
Can I stop it suddenly?
No. Stopping suddenly can cause your blood pressure to rise; if it needs to be stopped, this should be done gradually on your prescriber's advice.
Authoritative sources
- BNF
- NICE CKS
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