Rheumatology Department -LUHFT wide

What is bosentan and how is it used?

Bosentan is a medication which is used to help dilate blood vessels.

Why have I been given bosentan?

Bosentan is used for the treatment of digital ulcers, these are sores which usually appear on the fingers and toes. Digital ulcers are often seen in a condition called systemic sclerosis or scleroderma.

Why digital ulcers form is complex but is in part due to poor blood flow in the fingers. The drug bosentan reduces the number of new ulcers that appear.

How long will it take to work?

Bosentan does not work immediately. Your doctor will assess you after 6 months to see if it is helping. Unless you have side effects it is important to continue taking it even if you do not notice any change in your symptoms.

What dose do I take?

Your doctor will initially prescribe you 62.5mg twice a day. After four weeks they may advise you to increase the dose to 125mg twice daily

When and how to take bosentan

Bosentan is a tablet and should usually be taken twice a day (morning and evening). You should take bosentan at roughly the same time each day.

If you have missed a dose, take it as soon as you remember. If it is nearly time for the next dose, do not take the one you missed. Take the next dose at the usual time. Do not double the dose.

Do I need any specialist checks whilst on bosentan?

Before you start bosentan, if you are of child-bearing potential you will be given a pregnancy test. This is because bosentan is very harmful to the baby if taken in pregnancy.

Your doctor will also ensure that you are using a reliable form of contraception. Bosentan reduces the effectiveness of hormonal contraction (e.g., the oral contraceptive pill, implant and injections) increasing the chances of becoming pregnant.

Regular blood tests will be taken to check your blood counts and liver function tests. This will happen monthly or after any change in dose.

If you are of child-bearing potential you will need to have a pregnancy test taken monthly alongside your blood tests before your next prescription is given.

Possible risks and side effects

All medicines can cause unwanted side effects.

The most common side effects include:

  • Stomach upset, such as diarrhoea or indigestion.
  • Headache.
  • Stuffy nose.
  • Rash.

It can reduce the effectiveness of some contraceptive tablets so you will be advised about suitable contraception by your clinician

It can very rarely cause a serious problem with your liver, this is why we monitor you bloods closely when you are taking the drug. If we see abnormalities in your liver function tests we will advise you to stop the drug either for a temporary period or completely.

Some patients can have some changes in their blood counts so again we will monitor you closely and if we see abnormalities in your haemoglobin we will advise you to stop the drug either for a temporary period or completely.

While you are taking bosentan, contact your rheumatology specialist nurse straight away if you start experience any new symptoms or anything that concerns you. Let them know immediately if you have:

  • Nausea (urge to vomit) or vomiting.
  • Fever.
  • Stomach pain.
  • Jaundice (yellowing of the skin or the whites of your eyes).
  • Itching.
  • New severe tiredness.
  • Flu like symptoms.

 

Does bosentan interfere with other medications?

Bosentan can interact with other medications.

These include:

  • Glibenclamide.
  • Fluconazole.
  • Rifampicin.
  • Hormonal contraceptives.
  • Hormonal replacement therapy.
  • Ciclosporin.

Does bosentan affect fertility and pregnancy?

If you are planning a family or become pregnant while taking bosentan you should discuss this with your rheumatology team as soon as possible.

Bosentan is very harmful to a developing pregnancy. Bosentan is not recommended if you are breast feeding as it can be found in breast milk.

It is possible that bosentan if taken long-term can decrease fertility by reducing sperm count. Please discuss this with your rheumatology team if this is of concern to you.

Contraception advice can be accessed:

  • Via your GP.
  • The Axess clinic https://www.axess.clinic (0300 323 1300) which has multiple clinic sites across the region.

Feedback

Your feedback is important to us and helps us influence care in the future.

Following your discharge from hospital or attendance at your outpatient appointment you will receive a text asking if you would recommend our service to others. Please take the time to text back, you will not be charged for the text and can opt out at any point. Your co-operation is greatly appreciated.

 

Further information

Rheumatology Specialist Nurses 0151 529 3706/3034

Scleroderma and Raynaud’s UK (SRUK) www.sruk.co.uk

or Tel:020 3893 5998

 

Author: Rheumatology department

Review date: September 2026

PI 2188 V1