Patient leaflet - Macitentan 10 mg film-coated tablets
1. What Macitentan is and what it is used for
Macitentan contains the active substance macitentan, which belongs to the class of medicines called “endothelin receptor antagonists”.
Macitentan is used for the long-term treatment of pulmonary arterial hypertension (PAH):
- in adults of WHO Functional Class (FC) II to III
in children under 18 years and body weight of at least 40 kg with WHO Functional
Class (FC) II to III.
It can be used on its own or with other medicines for PAH. PAH is high blood pressure in the blood vessels that carry blood from the heart to the lungs (the pulmonary arteries). In people with PAH, these arteries get narrower, so the heart has to work harder to pump blood through them. This causes people to feel tired, dizzy, and short of breath.
Macitentan widens the pulmonary arteries, making it easier for the heart to pump blood through them. This lowers the blood pressure, relieves the symptoms and improves the course of the disease.
2. What you need to know before you take Macitentan
Do not take Macitentan
if you are allergic to macitentan, soya or any of the other ingredients of this medicine
(listed in section 6).
if you are pregnant, if you are planning to become pregnant, or if you could become
pregnant because you are not using reliable birth control (contraception). See section 'Pregnancy and breastfeeding'.
if you are breastfeeding. See section 'Pregnancy and breastfeeding'. · if you have liver disease or if you have very high levels of liver enzymes in your
blood. Talk to your doctor, who will decide whether this medicine is suitable for you. If any of these apply to you, please tell your doctor.
Warnings and precautions
Talk to your doctor or pharmacist before taking macitentan.
You will need blood tests, as indicated by your doctor:
Your doctor will take blood test before you start treatment with macitentan and during treatment to test:
- whether you have anaemia (a reduced number of red blood cells) · whether your liver is working properly
If you have anaemia (a reduced number of red blood cells), you may have the following signs:
- dizziness
- fatigue/malaise/weakness
- fast heart rate, palpitations
- pallor
If you notice any of these signs, tell your doctor.
Signs that your liver may not be working properly include:
- feeling sick (nausea)
- vomiting
fever
- pain in your stomach (abdomen)
- yellowing of your skin or the whites of your eyes (jaundice)
- dark-coloured urine
- itching of your skin
- unusual tiredness or exhaustion (lethargy or fatigue)
- flu-like syndrome (joint and muscle pain with fever)
If you notice any of these signs, tell your doctor immediately.
If you have kidney problems, talk to your doctor before using macitentan. Macitentan may lead to more reduction of blood pressure and decrease in haemoglobin in patients with kidney problems.
In patients with pulmonary veno-occlusive disease (obstruction of the lung veins), the use of medicines for treatment of PAH, including macitentan, may lead to pulmonary oedema. If you have signs of pulmonary oedema when using macitentan, such as a sudden, important increase in breathlessness and low oxygen, tell your doctor immediately. Your doctor may perform additional tests, and will determine what treatment regimen is most suitable for you.
Children and adolescents
Do not give this medicine to children below 2 years of age because efficacy and safety have not been established.
Other medicines and Macitentan
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicine.
Macitentan can affect other medicines.
If you take macitentan together with other medicines including those listed below, the effects of macitentan or the other medicines might be altered. Please talk to your doctor or pharmacist if you are taking any of the following medicines:
- rifampicin, clarithromycin, telithromycin, ciprofloxacin, erythromycin (antibiotics used to treat infections),
- phenytoin (a medicine used to treat seizures),
- carbamazepine (used to treat depression and epilepsy),
- St. John's Wort (an herbal preparation used to treat depression), · ritonavir, saquinavir (used to treat HIV infections),
- nefazodone (used to treat depression),
ketoconazole (except shampoo), fluconazole, itraconazole, miconazole, voriconazole
(medicines used against fungal infections),
- amiodarone (to control the heartbeat),
- cyclosporine (used to prevent organ rejection after transplant), · diltiazem, verapamil (to treat high blood pressure or specific heart problems)
Macitentan with food
If you are taking piperine as a dietary supplement, this may alter how the body responds to some medicinal products, including macitentan. Please talk to your doctor or pharmacist should this be the case.
Pregnancy and breastfeeding
If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, ask your doctor for advice before taking this medicine.
Macitentan may harm unborn babies conceived before, during or soon after treatment. · If it is possible you could become pregnant, use a reliable form of birth control
(contraception) while you are taking macitentan. Talk to your doctor about this. · Do not take macitentan if you are pregnant or planning to become pregnant. · If you become pregnant or think that you may be pregnant while you are taking macitentan, or shortly after stopping macitentan (up to 1 month), see your doctor immediately.
If you are a woman who could become pregnant, your doctor will ask you to take a pregnancy test before you start taking macitentan and regularly (once a month) while you are taking macitentan.
It is not known if macitentan is transferred to breast milk. Do not breastfeed while you are taking macitentan. Talk to your doctor about this.
Fertility
If you are a man taking macitentan, it is possible that this medicine may lower your sperm count. Talk to your doctor if you have any questions or concerns about this.
Driving and using machines
Macitentan can cause side effects such as headaches and hypotension (listed in section 4), and the symptoms of your condition can also make you less fit to drive or use machines.
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Macitentan contains lactose
If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.
Macitentan contains soya lecithin.
If you are allergic to soya, do not use this medicinal product. (see section 2 'Do not take Macitentan').
Macitentan contains sodium
This medicine contains less than 1 mmol sodium (23 mg) per film-coated tablet, that is to say essentially 'sodium-free'.
3. How to take Macitentan
Macitentan should only be prescribed by a doctor experienced in the treatment of pulmonary arterial hypertension.
Always take this medicine exactly as your doctor has told you. Check with your doctor if you are not sure.
Adults and children aged less than 18 years weighing at least 40 kg The recommended dose of macitentan is one 10 mg tablet, once a day. Swallow the whole tablet, with a glass of water, do not chew or break the tablet. You can take macitentan with or without food. It is best to take the tablet at the same time each day.
For children weighing less than 40 kg, macitentan is available as 2.5 mg dispersible tablets. Your doctor will advise you on your dosing.
If you take more Macitentan than you should
If you have taken more tablets than you have been told to take, you may experience headache, nausea, or vomiting. Ask your doctor for advice.
If you forget to take Macitentan
If you forget to take macitentan, take a dose as soon as you remember, then continue to take your tablets at the usual times. Do not take a double dose to make up for a forgotten tablet.
If you stop taking Macitentan
Macitentan is a treatment that you will need to keep on taking to control your PAH. Do not stop taking macitentan unless you have agreed this with your doctor.
If you have any further questions on the use of this medicine, ask your doctor or pharmacist.
4. Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them.
Uncommon serious side effects (may affect up to 1 in 100 people) · Allergic reactions (swelling around the eyes, face, lips, tongue or throat, itching
and/or rash)
If you notice any of these signs, tell your doctor immediately.
Very common side effects (may affect more than 1 in 10 people) · Anaemia (low number of red blood cells) or reduced haemoglobin · Headache
- Bronchitis (inflammation of the airways)
- Nasopharyngitis (inflammation of the throat and nasal passages) · Oedema (swelling), especially of the ankles and feet
Common side effects (may affect up to 1 in 10 people)
- Pharyngitis (inflammation of the throat)
- Influenza (flu)
- Urinary tract infection (bladder infection)
- Hypotension (low blood pressure)
- Nasal congestion (blocked nose)
- Elevated liver tests
- Leukopenia (decreased white blood cell counts)
- Thrombocytopenia (decreased blood platelet counts)
- Flushing (redness of the skin)
- Increased uterine bleeding
Side effects in children and adolescents
The side effects listed above may also be seen in children. Additional side effects very commonly seen in children include upper respiratory tract infection (infected nose sinuses, or throat) and gastroenteritis (inflamed stomach and gut). Rhinitis (itchy, runny, or blocked nose) was seen commonly in children.
Reporting of side effects
If you get any side effects talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via Yellow Card Scheme website www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
By reporting side effects you can help provide more information on the safety of this medicine.
5. How to store Macitentan
Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date which is stated on the blister and carton after EXP. The expiry date refers to the last day of that month.
This medicine does not require any special storage conditions.
Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
6. Contents of the pack and other information
What Macitentan contains
The active substance is Macitentan.
Each film-coated tablet contains 10 mg macitentan.
The other ingredients are:
Tablet core: Lactose monohydrate, sodium starch glycolate (Type-A), povidone (K-30), polysorbate 80, sodium stearyl fumarate.
Film coating: Polyvinyl alcohol (E1203), titanium dioxide (E171), talc (E553b), lecithin (E322), xanthan gum (E415).
What Macitentan looks like and contents of the pack
White colored, round, biconvex, film-coated tablets of 5.5 mm to 5.8 mm diameter debossed with "HM" on one side and "21" on other side.
Macitentan is available in blister packs containing 30 film-coated tablets and HDPE bottle pack containing 30 film-coated tablets.
Not all pack sizes may be marketed.
Marketing Authorisation Holder and Manufacturer
Amarox Limited
Congress House, 14 Lyon Road
Harrow, HA1 2EN
United Kingdom
This leaflet was last revised in 08/2026.
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