A medicine for high blood pressure in the lung arteries
Bosentan
An oral medicine that widens the lung arteries to treat pulmonary arterial hypertension, needing monthly liver blood tests.
What is Bosentan?
Bosentan is a tablet used to treat pulmonary arterial hypertension, which is high blood pressure in the arteries of the lungs. It belongs to a group called endothelin receptor antagonists, which relax and widen the lung arteries so the heart can pump blood through them more easily, easing breathlessness and helping you do more. It is started and supervised by a specialist pulmonary hypertension centre. It can affect the liver, so you will need regular blood tests, usually monthly, and it can harm an unborn baby, so reliable contraception is essential.
Education and reference only. This is a plain-language guide to Bosentan — 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
Bosentan is an oral medicine for pulmonary arterial hypertension, a serious condition where the blood pressure in the arteries between the heart and lungs is too high. This makes it hard work for the right side of the heart to push blood through the lungs, causing breathlessness, tiredness and a limited ability to be active. Bosentan is one of the endothelin receptor antagonists and is prescribed only through specialist pulmonary hypertension services in the UK, where treatment is carefully monitored.
How it works
In pulmonary arterial hypertension the lung arteries are narrowed and tightened, partly because of a natural substance called endothelin that makes blood vessels constrict. Bosentan blocks the receptors that endothelin acts on, so the lung arteries relax and widen. This lowers the pressure the heart has to pump against, which can ease breathlessness and improve how far someone can walk. It does not cure the condition but helps control it as part of a wider treatment plan.
Company & origin
Originated / developed by: Janssen (originator).
An endothelin receptor antagonist used in the UK by specialist centres to treat pulmonary arterial hypertension.
Practical use
How to take Bosentan
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth as directed by your pulmonary hypertension specialist, usually twice a day, swallowed with water.
- Attend all your blood test appointments, as regular liver and blood-count checks are an essential part of treatment.
- Use reliable contraception throughout treatment, and remember that hormonal contraception alone may not be enough — use an extra or alternative method.
- Do not stop the medicine suddenly without specialist advice, and keep taking it even when you feel well.
- Report any yellowing of the skin or eyes, dark urine, persistent nausea, tiredness or swelling of the ankles to your team.
Weighing it up
Advantages & disadvantages of Bosentan
Advantages
- Taken by mouth, avoiding the need for infusions or inhalations.
- Can ease breathlessness and improve how far you are able to walk in pulmonary arterial hypertension.
- Well established in specialist use, with a clear monitoring plan to keep treatment safe.
Disadvantages
- Can affect the liver, so regular blood tests, usually monthly, are needed throughout treatment.
- Can harm an unborn baby and may make hormonal contraception less reliable, so careful contraception is essential.
- May cause fluid retention and a drop in the blood count, and interacts with several other medicines.
Practical use
Good to know
Bosentan is a specialist medicine, so it is always started, supervised and reviewed by a pulmonary hypertension centre rather than a GP. The most important practical point is that it can affect the liver, so you will have blood tests before starting and then regularly, usually monthly, to check liver enzymes; you should report yellowing of the skin or eyes, dark urine, nausea or tummy pain. It can harm a developing baby, so it must not be used in pregnancy and effective contraception is essential throughout treatment and for a time afterwards; importantly, it can make hormonal contraception (such as the pill, patch or implant) less reliable, so an additional or alternative method is usually needed. It can also cause fluid retention and a fall in the blood count, which are watched for at clinic visits.
Who should not take it / use with caution
- Women who are pregnant, or who could become pregnant without reliable contraception, must not take it because it can harm the baby.
- People with significant existing liver disease or abnormal liver blood tests are usually not started on it.
- It is avoided with certain other medicines, such as ciclosporin and glibenclamide, that interact with it.
Monitoring
- Liver blood tests before starting and regularly, usually monthly, during treatment.
- Blood count checks to watch for anaemia, and review of fluid retention and weight.
- Regular specialist review of breathlessness, walking distance and overall response.
Side effects
- Headache, flushing and swelling of the ankles or legs from fluid retention are common.
- Liver enzyme changes on blood tests, which is why regular monitoring is needed.
- A fall in the blood count (anaemia), tiredness and, less often, low blood pressure.
Key interactions
- Can make hormonal contraception less reliable, so an additional or different method is needed.
- Interacts with ciclosporin and glibenclamide, which should not be taken with it.
- Levels can be changed by some antifungal and HIV medicines and by other pulmonary hypertension drugs, so the specialist team coordinates these.
Available as: Tablets, including dispersible tablets, taken by mouth.
Answers
Bosentan: frequently asked questions
Why do I need monthly blood tests?
Bosentan can affect the liver, so liver enzymes are checked before starting and then regularly, usually monthly, so any changes are picked up early and managed.
Can I take it if I might become pregnant?
No. It can harm an unborn baby, so it must not be used in pregnancy and reliable contraception is essential; hormonal contraception alone may not be enough.
Will it cure my pulmonary hypertension?
It does not cure the condition but helps control it by widening the lung arteries, which can ease breathlessness and improve what you are able to do.
Why are my ankles swelling?
Bosentan can cause fluid retention, leading to swollen ankles or legs; tell your specialist team, as it can be assessed and managed.
Can my GP prescribe it?
It is a specialist medicine started and supervised by a pulmonary hypertension centre, though your GP may help with practical aspects under their guidance.
Authoritative sources
- BNF
- NICE CKS
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