Ambrisentan belongs to the group of medications called endothelin receptor antagonists. These medications block the action of endothelin in the arteries of the lung that causes blood vessels to tighten or constrict. Ambrisentan is used to treat the symptoms of primary pulmonary arterial hypertension (PAH), or high blood pressure in the arteries of the lungs.

It is also used to treat pulmonary hypertension resulting from connective tissue diseases such as arthritis that have not adequately responded to other therapies for pulmonary hypertension.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual adult starting dose is 5 mg taken once daily. If tolerated, the dose can be increased to the maximum dose of 10 mg taken once daily. Ambrisentan can be taken with or without food.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

5 mg
Each square, pale pink, film-coated tablet engraved with "GS" on one side and "K2C" on the other contains 5 mg of ambrisentan. Nonmedicinal ingredients: microcrystalline cellulose, lactose monohydrate, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, talc, titanium dioxide and macrogol/polyethylene glycol 3350, lecithin, and FD&C Red No. 40 Aluminium Lake.

10 mg

Each oval, deep pink, film-coated tablet engraved with "GS" on one side and "KE3" on the other contains 10 mg of ambrisentan. Nonmedicinal ingredients: microcrystalline cellulose, lactose monohydrate, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, talc, titanium dioxide and macrogol/polyethylene glycol 3350, lecithin, and FD&C Red No. 40 Aluminium Lake.

Do not take this medication if you:

• are allergic to ambrisentan or any ingredients of the medication
• are pregnant or plan on becoming pregnant
• are breast-feeding
• have a lung condition called idiopathic pulmonary fibrosis (thickening or scarring of the lungs that makes breathing difficult)
• have severely decreased liver function or abnormal liver test results

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• constipation
• dizziness
• flushing
• headache
• nausea
• runny or stuffy nose
• sinus problems
• skin rash
• sore throat
• swelling of hands, feet, ankles, and legs
• tiredness or weakness
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• fluid retention, bloating
• palpitations (irregular or rapid heartbeat that you can feel)
• ringing in the ears
• severe abdominal pain
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of heart failure (e.g., shortness of breath, extreme tiredness, swelling in the ankles and legs)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• symptoms of low blood pressure (e.g., dizziness or fainting when rising from a sitting or lying position, blurred vision, nausea, vomiting, fatigue)
• vision changes or blurred vision
• worsening shortness of breath

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of an allergic reaction, e.g.:
• difficulty breathing
• hives
• rash
• swelling of the face or throat

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood changes: This medication may decrease hemoglobin levels and cause anemia (not enough red blood cells in your blood). Hemoglobin is the protein in red blood cells that carries oxygen throughout your body. Your doctor will perform regular tests to monitor your blood for changes while you are taking ambrisentan. People who have anemia should talk to their doctor before taking this medication. If you experience symptoms of anemia such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.

Fluid retention: Fluid buildup in the body can occur as a result of pulmonary arterial hypertension (PAH), but it can also be caused by this medication. This swelling is usually mild to moderate. However, tell your doctor if you experience symptoms of severe, increased swelling of your hands, feet, ankles, and legs while taking ambrisentan.

Liver function: This medication may cause liver damage. Your doctor will monitor your liver function by performing regular liver function tests while you are taking ambrisentan. Be sure to tell your doctor if you experience any signs of liver problems, such as yellowing of the skin or whites of the eyes, abdominal pain, or dark urine. If you have liver disease, discuss with your doctor how ambrisentan may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: Ambrisentan should not be used in pregnancy. Taking ambrisentan during pregnancy can cause serious birth defects. People who may become pregnant must not take ambrisentan until pregnancy is excluded. A pregnancy test must be performed before starting treatment with ambrisentan. A reliable form of birth control must be used at the same time during treatment with ambrisentan. Regularly pregnancy tests should be performed throughout treatment with ambrisentan. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if ambrisentan passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of this medication have not been established for children or adolescents under 18 years of age.

Seniors: People over the age of 65 are more likely to experience swelling of the hands, ankles, and feet while taking ambrisentan. Talk to your doctor if you have any concerns.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.