How do statins, such as atorvastatin, work to lower cholesterol levels?

Statins, including atorvastatin, primarily function by increasing the activity of LDL (low-density lipoprotein) receptors in the liver and reducing cholesterol production. Atorvastatin inhibits the enzyme HMG-CoA reductase, which plays a key role in the biosynthesis of cholesterol. By blocking this enzyme, statins decrease the synthesis of cholesterol within the liver cells, leading to a subsequent reduction in intracellular cholesterol levels.

As a result of decreased cholesterol production, the liver compensates by increasing the expression of LDL receptors on its surface. These receptors are responsible for clearing LDL cholesterol from the bloodstream by binding to it and facilitating its uptake into the liver. The net effect of these two mechanisms—enhanced LDL receptor activity and diminished cholesterol synthesis—results in a significant reduction in serum LDL cholesterol levels. This action contributes to the overall cardiovascular benefits associated with statin therapy, including reducing the risk of heart disease and stroke.

The other options listed involve different mechanisms unrelated to how statins function. Vitamin K epoxide reductase inhibition pertains to anticoagulant drugs like warfarin, cyclooxygenase inhibition is related to nonsteroidal anti-inflammatory drugs (NSAIDs), and calcium channel blockers are used in managing hypertension and other cardiac conditions.