A Review of Antihypertensive Medications, Part I

Multiple classes of antihypertensive medications are employed in treating hypertension. The most commonly recommended first-line treatments include:Thiazide Diuretics, such as chlorthalidone, increase sodium and water excretion from the body, reducing blood volume and blood pressure.Angiotensin-converting enzyme inhibitors, like lisinopril, block the conversion of angiotensin I to II, a potent vasoconstrictor lowering blood pressure.Angiotensin II Receptor Blockers (ARBs) prevent angiotensin II...

In the renin-angiotensin-aldosterone system, a hormone called angiotensin II plays a crucial role. It binds to the AT1 receptors in vascular smooth muscles coupled with Gq proteins. The activation of these receptors activates an enzyme called phospholipase C, which releases two molecules: inositol trisphosphate and diacylglycerol. These molecules cause a chain reaction that leads to the phosphorylation of myosin light chains and promotes interaction between actin and myosin, leading to smooth...

The renin-angiotensin-aldosterone system (RAAS) is an intricate physiological pathway involving numerous enzymes and hormones, including renin, angiotensin-converting enzyme (ACE), angiotensin I and II, and aldosterone. Imbalances within this system increase the production of angiotensin II and aldosterone. Increased angiotensin II levels promote vasoconstriction and blood pressure elevation. Concurrently, higher aldosterone levels stimulate sodium and water reabsorption in the kidneys,...

Angiotensin-converting enzyme (ACE), a vital component of the renin-angiotensin-aldosterone system, is abundant in lung endothelial cells. ACE converts the inactive decapeptide, angiotensin I, into the active octapeptide, angiotensin II. This potent vasoconstrictor narrows blood vessels, increasing resistance to blood flow and elevating blood pressure. Angiotensin II also stimulates aldosterone production, encouraging kidney cells to reabsorb more sodium and water from urine, thereby increasing...

Vasodilators, primarily affecting the smooth muscles within arterial and venous walls, are commonly used for hypertension treatment. Medications such as minoxidil and hydralazine primarily target arteries and arterioles, while sodium nitroprusside acts on arterioles and venules. Minoxidil, functioning as a prodrug, is metabolized by hepatic sulfotransferase into its active form, minoxidil sulfate, after oral administration. This metabolite binds to the sulfonylurea receptor (SUR) component of...

Diuretics are antihypertensive drugs used to treat hypertension resulting from sodium and water retention. Sodium, vital for fluid balance and nerve or muscle function, is regulated by the kidneys through millions of nephrons. Blood enters nephrons via afferent arterioles, which branch into capillaries called glomeruli. These filter blood plasma, allowing water and solutes, like sodium ions, to pass through capillary walls into Bowman's capsule. The filtrate then flows through various...