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Macitentan

Drug Class: Commonly Known As: Category:
Endothelin Receptor Antagonist Opsumit Adult

Macitentan - What is it for

Macitentan is used to treat pulmonary arterial hypertension. It is an endothelin receptor antagonist (ERA) that lowers the pressure in the pulmonary arteries (blood vessels in the lungs that transfer oxygen into the blood) by blocking the effects of endothelin. It may have the potential to reverse some of the damage done by the condition. This should also improve symptoms such as breathlessness and increase your ability to exercise.

This medication may also be used for other conditions as determined by your doctor.

Macitentan - Side Effects, Precautions, and Contraindications

What side effects can Macitentan cause?

Common side effects include:

  • Flushing, low blood pressure, fainting or headache
    • Rise slowly from a sitting or lying position to reduce giddiness when changing position
  • Leg swelling (oedema)
  • Flu-like symptoms such as nose and throat irritation, stuffy nose or back pain
  • Urinary tract infection (trouble or pain passing urine), inform your Cardiologist or Nurse.

These side effects may be minimised by starting with a lower dose and may improve or go away with time. Inform your healthcare professional if it becomes bothersome or does not go away.

Rare but serious side effects include:

  • Changes in liver function: Signs include dark urine or light coloured stools, nausea, vomiting, loss of appetite, stomach pain, yellowing of your eyes or skin.
  • Low haemoglobin levels (anaemia): Signs include feeling more tired, weak or shortness of breath.

These side-effects are usually not significant, they are often treatable once detected early. You will need frequent blood tests to monitor for them.

The symptoms of a drug allergy include one or more of the following: 

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

Before taking Macitentan, what precautions must I follow?

Inform your healthcare professional if:

  • You are allergic to this medication or any of the other ingredients of this medication.
  • You are pregnant, planning to become pregnant, or breastfeeding.
    • As this medication may cause birth defects, female patients of childbearing age should take precautions by using at least 2 reliable methods of contraception to avoid pregnancy. If you suspect you may be pregnant, inform your doctor as soon as possible.
    • You should not become pregnant for at least 1 month after stopping this medication.
  • You have or have had liver or kidney disease.
  • You are taking any other medications, including supplements, traditional medications and herbal remedies.

What food or medicine must I avoid when I take Macitentan?

Avoid taking grapefruit when you are taking this medicine as grapefruit may interact with your medicine and increase the risk of side-effects.

Some medications may interact with Macitentan and affect their effectiveness or increase the risk of side effects. However, these medications may also be important for your treatment. Inform your healthcare professional of the other medications you are currently taking. Examples include:

  • Medications for bacterial infections (e.g. clarithromycin, erythromycin)
  • Medications for fungal infections (e.g. itraconazole, ketoconazole)

Consult your healthcare professional if you are unsure whether your existing medications can be taken together with this medication.

Macitentan - Dosage and How to Use

How should Macitentan be used?

  • Do not stop taking your medication without checking with your healthcare professional as it may make your condition worse.
  • You may take this medication with or without food. 
  • This medication is initially started at a lower dose. Your condition will be monitored closely. Your doctor may later adjust your dosage to better control your condition.

What should I do if I miss a dose?

If you forget to take a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What should I do if I overdose?

Macitentan - Handling

How should I handle Macitentan safely?

Macitentan - Storage

How should I store Macitentan?

Keep away from children;#Keep in a cool, dry place, away from direct sunlight;#

How should I dispose of Macitentan safely?

​Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.

Macitentan - Additional Information

  • Updated on Wednesday, September 30, 2020
  • Article contributed by PSS National Medication Information Workgroup PSS National Medication Information Workgroup

    The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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