Valsartan is a potent and specific orally active angiotensin II receptor antagonist. It acts selectively on the AT1 receptor subtype, responsible for the known actions of theangiotensin II. Elevated plasma angiotensin II levels after AT1 receptor blockade with valsartan may stimulate the AT2 receptor subtype without blocking, which appears to counteract theAT1 receptor effect. Valsartan shows no partial agonist activity on the AT1 receptor and has a much higher affinity (approximately 20,000 times) for the AT1 receptor than forthe AT2 receptor.