Advanced Dental Admission Test (ADAT)

What is the primary inhibitory action of statin drugs?

1. Phospholipase C

2. HMG-CoA reductase

3. Thromboxane synthesis

4. Corticosteroid production

The correct answer is: HMG-CoA reductase

The primary inhibitory action of statin drugs is to inhibit HMG-CoA reductase, which is a key enzyme in the cholesterol biosynthesis pathway. By blocking this enzyme, statins effectively reduce the synthesis of mevalonate, a precursor to cholesterol. This decrease in cholesterol production leads to a reduction in circulating cholesterol levels, particularly low-density lipoprotein (LDL) cholesterol, which is often referred to as "bad" cholesterol due to its association with an increased risk of cardiovascular diseases. Statins are widely used in clinical practice to manage dyslipidemia and to reduce the risk of heart attacks and strokes. The impact of statins extends beyond cholesterol lowering; they have additional pleiotropic effects, including anti-inflammatory actions and improving endothelial function. Other options reflect processes not primarily affected by statins. Phospholipase C is involved in cell signaling pathways but is unrelated to the cholesterol synthesis pathway. Thromboxane synthesis pertains to platelet aggregation and is not directly influenced by statins. Corticosteroid production is related to adrenal hormone regulation and has no direct link to the mechanism of action of statin drugs. Therefore, the focus on HMG-CoA reductase is what defines the primary effect of statins in cholesterol