PAdrenoceptor Blockers

In most elderly patients with essential hypertension, cardiac output is low, and systemic vascular resistance is elevated. Therefore, most antihypertensive agents, including diuretics, produce a decrease in vascular resistance while sparing systemic flow and cardiac output. Traditional ^-adrenoceptor blockers (^-selective b-blockers) (Figure 8) are an exception as drugs such as atenolol and metoprolol lower arterial pressure by decreasing cardiac output and renin

Figure 8 Structures of ß-adrenoceptor and calcium channel blockers.

release while systemic vascular resistance remains unchanged. The use of ^-adrenoceptor blockers reduces the risk of cardiovascular events such as myocardial infarction and sudden death in patients with coronary artery disease. b-Adrenoceptor blockers are effective in decreasing mortality rate in patients with reduced systolic function and heart failure.64 Carvedilol, a b-adrenoceptor blocker with associated ^-adrenoceptor blocking properties is an effective antihypertensive medication where the ^-adrenergic blocking effect accounts for its vasodilatory effects in contrast to the bi-selective agents.

Early stage renal disease in hypertension is characterized by a decrease in renal blood flow and a relatively well-preserved GFR. Microproteinuria parallels the progression of renal disease, particularly in hypertensive patients with diabetes mellitus. Traditional b-adrenoceptor blockers further diminish renal blood flow and may decrease GFR.65 One of the main side effects of using b-adrenoceptor blockers is the disturbance of the lipid profile. Studies suggest that b-adrenoceptor blockers increase triglyceride levels and decrease HDL cholesterol levels. Those with intrinsic sympathomimetic activity have a lesser effect on triglycerides and HDL than those lacking intrinsic sympathetic activity.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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