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Angiotensin II receptor blockers (ARBs) are a class of medications primarily used to treat high blood pressure and heart failure. They work by blocking the effects of angiotensin II, a hormone that causes blood vessels to constrict, leading to increased blood pressure.
Mechanism of Action of ARBs
ARBs selectively block the angiotensin II type 1 (AT1) receptors. By inhibiting these receptors, they prevent angiotensin II from exerting its vasoconstrictive and aldosterone-secreting effects. This results in vasodilation, reduced blood volume, and decreased blood pressure.
Unlike ACE inhibitors, ARBs do not inhibit the breakdown of bradykinin, which reduces the risk of certain side effects such as cough and angioedema.
Therapeutic Uses of ARBs
- Hypertension: ARBs are commonly prescribed to lower blood pressure.
- Heart Failure: They help improve symptoms and reduce mortality in heart failure patients.
- Prevention of Stroke: ARBs can be used to reduce the risk of stroke in hypertensive patients.
- Diabetic Nephropathy: They protect kidney function in patients with diabetes.
- Chronic Kidney Disease: ARBs slow the progression of kidney damage.
Common ARBs and Their Examples
- Losartan
- Valsartan
- Candesartan
- Irbesartan
- Olmesartan
ARBs are generally well tolerated, with side effects including dizziness, hyperkalemia, and, less commonly, kidney dysfunction. They are contraindicated in pregnancy and should be used cautiously in patients with renal impairment.
Conclusion
Understanding the mechanism and therapeutic applications of ARBs enhances their effective use in clinical practice. Their ability to lower blood pressure and protect organ function makes them valuable in managing cardiovascular and renal diseases.