Angiotensin II Receptor Antagonists

The heart is a beating muscle that pumps blood to the body through a network of arteries. The force of the blood is constantly putting pressure on the inside walls of blood vessels. This is known as “blood pressure”. Blood pressure is measured to evaluate the force and amount of blood being pumped from the heart, as well as the flexibility and condition of the vessels. Many different factors can affect blood pressure including: - the levels of hormones in the body - water and salt content - and the condition of the heart, kidneys, nervous system, and blood vessels. Blood pressure is closely regulated by chemicals in the body that change the diameter of the blood vessels depending on the needs of the body: widening to let more blood flow or narrowing to allow less blood to flow. For example, a chemical called “angiotensin II” helps regulate blood vessel narrowing. Angiotensin II is created through a series of chemical reactions that take place in the body. In order to cause vessel narrowing, angiotensin II binds to proteins, called AT1 receptors, on the surface of smooth muscles within the blood vessels. Once bound, the smooth muscle cells tighten, decreasing the width of the blood vessel. Too much angiotensin II circulating in the bloodstream results in prolonged vessel tightening, or high blood pressure. Hypertension, or high blood pressure, is a condition where blood pressure remains abnormally high. If left untreated, hypertension can seriously damage the heart and blood vessels by adding to their workload. This can result in congestive heart failure, stroke, heart attack, kidney damage, aneurysms, or even death. Many factors can cause blood pressure to remain elevated, specifically conditions that cause narrowing of blood vessels. To treat hypertension, a class of Antihypertensive medications called “angiotensin II receptor antagonists” may be prescribed. By attaching to AT1 receptors on smooth muscle cells lining the blood vessels, this drug blocks angiotensin II from binding. This action prevents angiotensin II from causing the smooth muscle cells to contract. The end result is that angiotensin II receptor antagonists prevent blood vessels from narrowing, thereby keeping a normal blood pressure. There are several different brands of angiotensin II receptor antagonists. As with all medications, adverse effects may develop while taking this medication. It is important to always consult with your doctor about high blood pressure medications.