What is the mechanism of action of HMG CoA reductase inhibitors like rosuvastatin?

HMG CoA reductase inhibitors, commonly known as statins, work by inhibiting the enzyme HMG-CoA reductase, which plays a crucial role in the cholesterol biosynthesis pathway. By blocking this enzyme, statins decrease the conversion of HMG-CoA to mevalonate, an early and vital intermediate in cholesterol synthesis. This reduction in mevalonate synthesis leads to lower levels of cholesterol produced by the liver.

As a result of decreased cholesterol production, the liver increases the expression of LDL receptors on its surface. This increase enhances the uptake of LDL cholesterol from the bloodstream, ultimately lowering plasma LDL cholesterol levels and reducing the risk of cardiovascular events. The action of statins thus contributes significantly to cholesterol management in patients at risk for heart disease.

In this context, options that suggest increased cholesterol or inhibition of LDL receptors do not reflect the fundamental mechanism of how rosuvastatin and other statins operate. Instead, the correct focus on the inhibition of mevalonate synthesis highlights the primary way these medications achieve their lipid-lowering effects.