Indications
Macitentan is used for the long-term treatment of pulmonary arterial hypertension (PAH), a condition in which the blood vessels in the lungs become narrow and stiff, so the right side of the heart has to work harder. It helps slow the worsening of the disease and improves the ability to exercise. It may be used alone or together with other PAH medicines.
How It Works
Macitentan is an endothelin receptor antagonist. Endothelin is a natural substance that tightens blood vessels and makes their walls thicken. By blocking the receptors that endothelin acts on, Macitentan helps the lung blood vessels relax and reduces the pressure in them.
Dosage and Administration
The usual adult dose is 10 mg taken by mouth once a day, with or without food. Swallow the tablet whole with water and take it at about the same time each day. Do not stop taking it without speaking to your specialist. Treatment is started and monitored by a doctor experienced in pulmonary hypertension.
Interactions
- Strong enzyme inducers such as Rifampicin, Carbamazepine, Phenytoin and St John’s wort can lower Macitentan levels and should be avoided.
- Strong enzyme inhibitors such as Ketoconazole, Itraconazole, Clarithromycin and Ritonavir can raise Macitentan levels.
- Tell your doctor about all medicines, including hormonal contraceptives and herbal products.
Contraindications
- Pregnancy, or women who could become pregnant and are not using reliable contraception.
- Severe liver disease or liver enzymes more than three times the upper normal limit.
- Breastfeeding.
- Allergy to Macitentan or any ingredient of the tablet.
Side Effects
Common side effects include a drop in haemoglobin (anaemia), stuffy or runny nose, sore throat, headache, flu-like illness, urinary tract infection and swelling of the legs or ankles from fluid build-up. Liver test changes can occur.
Get urgent medical help if you notice yellow skin or eyes, dark urine, severe tiredness or pain in the upper right belly, sudden worsening breathlessness, fainting, or signs of an allergic reaction such as swelling of the face or difficulty breathing.
Pregnancy and Lactation
Macitentan can cause serious birth defects and must not be taken during pregnancy. Women who can become pregnant need a negative pregnancy test before starting, monthly tests during treatment and reliable contraception during treatment and for one month after stopping. It must not be used while breastfeeding.
Precautions and Warnings
Your doctor will check your haemoglobin and liver tests before starting and during treatment. Tell your doctor if you have kidney problems, low blood pressure or lung vein disease (pulmonary veno-occlusive disease), as fluid can build up in the lungs. In men, medicines of this class may reduce sperm count. Dizziness may affect driving.
Overdose
Taking too much may cause headache, nausea, vomiting and low blood pressure. Contact a doctor or go to the nearest hospital, taking the pack with you. Treatment is supportive.
Therapeutic Class
Endothelin receptor antagonist; medicine for pulmonary arterial hypertension.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Keep the tablets in the original pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.