Ambrisentan is an endothelin receptor antagonist that blocks the endothelin A receptor on vascular smooth muscle cells and cardiac myocytes, preventing vasoconstriction and smooth muscle cell proliferation.
The recommended dose of Volibris is 5mg once daily. Some additional efficacy has been observed with 10mg once daily in patients with class III symptoms, however an increase in peripheral oedema has also been observed.
Patients with associated connective tissue disease may require 10mg once daily.
Volibris is currently the only drug licensed for patients with class II pulmonary arterial hypertension.
Further information: GlaxoSmithKline