Final answer:
β-blockers lower blood pressure by blocking the stimulatory effects of adrenaline on the heart and blood vessels. They are commonly used to treat hypertension and other cardiovascular diseases. Medications like metoprolol and propranolol are examples of β-blockers.
Step-by-step explanation:
β-blockers are a class of medications that have a significant effect on blood pressure (BP). They work by binding to G-protein-linked receptors, specifically the β-1 receptors, on heart muscles and block the action of adrenaline (also known as epinephrine and norepinephrine or NE). Adrenaline normally has a stimulatory effect on heart rate and blood pressure by causing vasoconstriction and increasing the heart rate. β-blockers act antagonistically to adrenaline, resulting in a decrease in heart rate and dilatation of blood vessels, which ultimately lowers blood pressure.
Common medications within the β-blocker class include metoprolol, which specifically targets β-1 receptors, and propranolol, which blocks β-receptors more broadly. These drugs are essential in treating cardiovascular conditions by preventing excessive cardioacceleration and vasoconstriction. However, caution is advised as overprescription may lead to bradycardia or, in severe cases, cardiac arrest.
For patients with hypertension, it's important to maintain BP levels below 140/90 mmHg, and β-blockers are recommended as one of the first-line treatments for achieving this target. They are distinct from other antihypertensive drugs like ACE inhibitors, which block the conversion of angiotensin I to angiotensin II, another agent that can elevate BP.