Ambrisentan

• While taking ambrisentan you should see your treating specialist regularly to make sure the treatment is working, and to minimise any possible side effects.
• Ambrisentan should be taken at the same time each day.
• You should not stop your treatment unless your doctor tells you to.
• You should not increase or reduce the dose of ambrisentan unless your doctor tells you to.
• Contact your doctor at once if you experience symptoms such as nausea, stomach pain, fever, loss of appetite, dark urine, clay-coloured stools or jaundice (yellowing of the skin or eyes).
• Ambrisentan interacts with many other drugs. Discuss with your doctor whether you need to change the doses of these drugs or avoid using them together with ambrisentan.

Ambrisentan helps lower blood pressure in the lungs by opening up the lung blood vessels. This helps your heart pump blood through the blood vessels in the lungs more efficiently.

Ambrisentan can reduce the symptoms of PAH and in some cases prolong life expectancy. It may take up to 2 months or more before your symptoms start to improve.
Before ambrisentan can be prescribed, a specialise will assess you. This may be a rheumatologist, immunologist, cardiologist (heart) or respiratory (lung) physician who has  experience in managing PAH.

You will be asked to have the following tests:

• an ultrasound scan of your heart (echocardiogram)
• a right heart catheter – this is a test to measure the blood pressures in your heart and lungs. It involves inserting a tube into your heart from an artery in your neck, arm or groin.
• a six minute walk test (6MWT) to measure how far you can walk in six minutes.

Every six months you will be asked to have the echocardiogram and the 6MWT to check that ambrisentan is still helping your condition.

Ambrisentan is a tablet. It comes in two strengths (5mg and 10mg).

What is the dosage and when should it be taken?

The normal starting dose is 5mg once a day. In some cases the dose may be increased by your doctor to 10mg once a day.

Ambrisentan should be taken at the same time each day. It is usually taken in the morning or at night. If you forget to take a tablet you can take it later in the day. If it is the next day, take the normal dose (do not take a double dose). It does not have to be taken with food.

Can other medicines be taken with ambrisentan?

Ambrisentan may be taken in combination with other medicines, including:

• steroid medicines such as prednisolone
• anti-inflammatory medicines (NSAIDs) such as naproxen (Naprosyn) or ibuprofen (Brufen/Nurofen) provided your kidney and heart function are normal
• pain-relieving medicines such as paracetamol and combined medicines such as Panadeine and Panadeine Forte
• calcium channel blockers (for Raynaud’s disease)
• diuretics (fluid tablets)
• warfarin (blood-thinning medicine)
• other treatments for PAH.

There are a number of medicines that should not be taken when you are taking ambrisentan.

How long is the treatment continued?

Ambrisentan may be given on a long-term basis provided it does not cause problems and continues to help your condition. It is usually given for as long as the 6-monthly tests (echocardiogram and 6MWT) show that it is of benefit.

Do not stop taking ambrisentan without first talking to your doctor. If your doctor decides to stop the treatment you may need to reduce the dose gradually before you stop the medicine completely.

Most people who take ambrisentan do not experience side effects. Tell your doctor if you are worriedabout possible side effects. Having a lower dose may reduce side effects so that you can continue taking ambrisentan.

Most common possible side effects

• The most common side effects include stomach upset, nausea, diarrhea and headache.
• Other side effects include inflamed throat, irritated nose passages or skin rash.
• Dizziness due to low blood pressure, flushing, ankle and/or leg swelling can occur.
• Irregular heart beats or tiredness have been reported.

Less common or rare possible side effects

• Ambrisentan can cause severe liver problems. Symptoms include nausea, stomach pain, low fever, loss of appetite, dark urine, clay-coloured stools and jaundice (yellowing of the skin or eyes). Call your doctor at once if you have any of these symptoms.
• Low haemoglobin (anaemia) can be detected on blood tests but rarely causes symptoms.
• There are also a number of other rare side effects.

Blood tests

• Your liver function and blood counts for haemoglobin will need to be tested before you start taking ambrisentan, and again each month during your treatment.

Use with other medicines

• Ambrisentan can interact with other medicines. You should tell your doctor (including your GP, rheumatologist and other health professionals) about all medicines you are taking or plan to take. This includes over-the-counter or herbal/naturopathic medicines.
  • The following medicines may interfere with ambrisentan. Some should not be taken with ambrisentan. For others, the dose may need to be adjusted.
  • cyclosporin (Cicloral, Neoral, Sandimmune)
  • cholesterol lowering medicines
  • anti-fungal medicines
  • HIV/AIDS medicines lopinavir or ritonavir (Kaletra, Norvir)
  • tacrolimus (used to prevent rejection of liver or kidney transplants)
  • rifampicin (used for tuberculosis).
• Ambrisentan does not increase the risk of side effects from low-dose aspirin (taken for prevention of heart attack and strokes).

Vaccines

• Most vaccines can be given safely with ambrisentan. Pneumovax and yearly flu vaccinations are safe and recommended to reduce your risk of those infections. Talk with your rheumatologist before receiving any vaccines.

Use during pregnancy and breastfeeding

• Ambrisentan should not be taken during pregnancy or when breastfeeding.
• If you are a woman of childbearing age, you should use effective contraception while taking ambrisentan.
• If you are planning a family or you become pregnant during your treatment, you should discuss this with your doctor as soon as possible.

• Store ambrisentan at room temperature, away from heat, moisture and light (e.g. not in the bathroom).
• Keep all medicines out of reach of children.