Author(s): Velasquez MT
Angiotensin II (AII) receptor antagonists, a new class of antihypertensive agents, recently became available for the treatment of clinical hypertension. These agents have a unique mechanism of action: they selectively block the AII receptor type I thereby blocking all known physiological actions of AII that are relevant to hypertension. Controlled clinical trials have shown losartan potassium, the first of the AII receptor type I antagonists approved for clinical use, to be effective, providing long-term control of blood pressure in once daily oral doses in patients who have mild to moderate essential hypertension. Losartan is as efficacious as enalapril maleate and atenolol in these patients. Its antihypertensive effect is enhanced when used in combination with a thiazide diuretic. Losartan is well tolerated and generally free of the side effects that are commonly associated with angiotensin converting enzyme inhibitors and other currently available antihypertensive drugs. Thus, AII receptor blockers represent an important therapeutic advance in treating hypertension and provide a targeted treatment approach to block activation of the renin-angiotensin system.