Angiotensin II receptor blocker: A medication that blocks the action of angiotensin II, permitting the blood vessels to relax and dilate (widen), which lowers the blood pressure. Abbreviated ARB.

ARBs are used to control high blood pressure (hypertension), treat heart failure, and prevent kidney failure in people with diabetes or high blood pressure. Since the ARBs have effects similar to those of ACE inhibitors, they are often used when an ACE inhibitor cannot be tolerated by patients. The ARBs include: irbesartan (Avapro), candesartan (Atacand), losartan (Cozaar), valsartan (Diovan), telmisartan (Micardis), eprosartan (Tevetan), and olmesartan (Benicar).

The most common side effects from ARBs are cough, elevated potassium levels (hyperkalemia), low blood pressure (hypotension), dizziness, headache, drowsiness, diarrhea, a metallic or salty taste, and rash. ARBs are usually not prescribed for pregnant patients or individuals with severe kidney problems.