Angiotensin II receptor blockers are medications that inhibit the release of a hormone that increases the amount of sodium and water in the body, causing a rise in blood pressure. This hormone also narrows and stiffens the walls of the blood vessels and heart. Angiotensin II receptor blockers, which are sold under various trade names, alleviate hypertension by allowing blood vessels to dilate, according to the Mayo Clinic.
Angiotensin II receptor blockers are prescribed for hypertension and to prevent heart disease, kidney failure due to diabetes, chronic kidney disease and scleroderma, a thickening and hardening of the skin. Angiotensin II is the most powerful known constrictor of blood vessels, states MedicineNet. These drugs work by blocking angiotensin receptors in the small arteries. Angiotensin-converting enzyme inhibitors perform the same action but have side effects such as a persistent dry cough.
Women who are pregnant or planning a pregnancy are advised not to take angiotensin II receptor blockers because the medication has been linked to birth defects. These drugs may interact with pain relievers, antacids, potassium supplements, certain diuretics and lithium. All patients who are taking an angiotensin II receptor blocker should have their blood tested regularly to monitor its effects on their cardiovascular system, according to WebMD.