Ambrisentan

An endothelin receptor antagonist used in the treatment of pulmonary arterial hypertension

Chemical structure of Ambrisentan

Ambrisentan is a medication that belongs to the class of drugs known as endothelin receptor antagonists. It is primarily used in the treatment of pulmonary arterial hypertension (PAH), a condition characterized by high blood pressure in the arteries of the lungs.

Mechanism of Action

Ambrisentan works by blocking the action of endothelin, a potent vasoconstrictor peptide that contributes to the narrowing of blood vessels. By inhibiting the binding of endothelin to its receptors, Ambrisentan helps to relax and widen the blood vessels, thereby reducing the blood pressure in the pulmonary arteries and improving blood flow.

Pharmacokinetics

Ambrisentan is administered orally and is well absorbed from the gastrointestinal tract. It has a bioavailability of approximately 70% and reaches peak plasma concentrations within 1.5 to 2 hours after ingestion. The drug is extensively metabolized in the liver, primarily by glucuronidation, and is excreted mainly in the urine and feces.

Clinical Use

Ambrisentan is indicated for the treatment of pulmonary arterial hypertension in patients with WHO Group I PAH to improve exercise capacity and delay clinical worsening. It is often used in combination with other PAH therapies, such as phosphodiesterase type 5 inhibitors or prostacyclin analogs.

Side Effects

Common side effects of Ambrisentan include peripheral edema, nasal congestion, and headache. It may also cause liver function abnormalities, and regular monitoring of liver enzymes is recommended during treatment. Ambrisentan is contraindicated in pregnancy due to the risk of fetal harm.

Related pages

• Pulmonary arterial hypertension
• Endothelin receptor antagonist
• Vasodilator