Pharmacy PEBC Practice Exam

What is the mechanism of action for statins?

1. Enhancing cholesterol production

2. Blocking sugar absorption

3. Inhibiting HMG-CoA reductase

4. Increasing blood pressure

The correct answer is: Inhibiting HMG-CoA reductase

Statins exert their pharmacological effect primarily through the inhibition of HMG-CoA reductase, which is a key enzyme in the cholesterol biosynthesis pathway. By blocking this enzyme, statins effectively reduce the end product of cholesterol synthesis in the liver. This leads to a decrease in the overall levels of cholesterol in the blood, particularly low-density lipoprotein (LDL) cholesterol, which is often referred to as "bad" cholesterol. Inhibition of HMG-CoA reductase not only reduces the cholesterol levels but also prompts the liver to upregulate LDL receptors on its surface. As a result, more LDL cholesterol is removed from the bloodstream, further contributing to lowered levels of circulating cholesterol. This metabolic shift is crucial for managing and reducing the risk of cardiovascular diseases, such as heart attacks and strokes, associated with elevated cholesterol levels. The other mechanisms listed are not related to the action of statins. For instance, enhancing cholesterol production would directly oppose the action of statins, as their goal is to lower cholesterol levels. Blocking sugar absorption pertains more to medications used for diabetes management rather than cholesterol control. Finally, increasing blood pressure is unrelated to the function of statins, which aim primarily at lipid regulation rather than hemodynamic effects.