Chapter 44: Antihyperlipidemics & Peripheral Circulation Drugs

Antihyperlipidemics & Peripheral Circulation Drugs begins by categorizing lipoproteins, distinguishing between the protective High-Density Lipoprotein (HDL) which facilitates cholesterol removal, and the atherogenic Low-Density Lipoprotein (LDL) and Very-Low-Density Lipoprotein (VLDL) which deposit cholesterol in arterial walls, increasing the risk of Coronary Artery Disease (CAD). The text emphasizes that nonpharmacologic strategies, such as dietary reductions in saturated fats, exercise, and smoking cessation, are primary interventions, though genetic factors often necessitate drug therapy. Detailed classifications of antihyperlipidemics include bile-acid sequestrants like cholestyramine and colesevelam, which lower LDL by binding bile acids in the intestine; fibrates (fibric acid derivatives) such as gemfibrozil and fenofibrate, which are highly protein-bound and primarily effective at lowering triglycerides and VLDL; and niacin (Vitamin B3), which improves lipid profiles but is often limited by side effects like cutaneous flushing and hepatotoxicity. Significant attention is dedicated to cholesterol absorption inhibitors like ezetimibe and the widely prescribed HMG-CoA reductase inhibitors, known as statins (e.g., atorvastatin, rosuvastatin, simvastatin). Statins function by inhibiting the enzyme responsible for hepatic cholesterol biosynthesis, significantly lowering LDL, but require vigilant monitoring for elevated liver enzymes and rhabdomyolysis, a potentially fatal muscle disintegration. The chapter also explores biomarkers like homocysteine and high-sensitivity C-reactive protein (hsCRP) as indicators of inflammatory cardiovascular risk. Furthermore, the text addresses Peripheral Arterial Disease (PAD), manifested by intermittent claudication and cool extremities, outlining treatments with peripheral vasodilators like cilostazol, an antiplatelet agent that dilates femoral vasculature, and pentoxifylline, a blood viscosity reducer that improves microcirculation by enhancing erythrocyte flexibility.