Angiotensin II receptor blockers, formally angiotensin II receptor type 1 antagonists, also known as angiotensin receptor blockers, angiotensin II receptor antagonists, or AT1 receptor antagonists, are a group of pharmaceuticals that bind to and inhibit the angiotensin II receptor type 1 and thereby block the arteriolar contraction and sodium retention effects of renin–angiotensin system. Wikipedia