Atorvastatin is a type of drug known as a statin, which is primarily used to lower cholesterol levels in the blood. It achieves this by inhibiting the enzyme HMG-CoA reductase, a key player in the production of cholesterol within the body [1].

The HMG-CoA reductase enzyme is responsible for converting HMG-CoA to mevalonate, an early step in the cholesterol synthesis pathway. By inhibiting this enzyme, atorvastatin reduces the production of cholesterol, leading to a decrease in blood cholesterol levels [1].

Additionally, atorvastatin has been shown to increase the number of LDL receptors in the liver, which results in increased clearance of LDL (low-density lipoprotein) or "bad" cholesterol from the bloodstream [1].

In summary, atorvastatin reduces cholesterol by inhibiting HMG-CoA reductase, thereby decreasing cholesterol production, and increasing the clearance of LDL cholesterol from the bloodstream.

Sources:
[1] DrugPatentWatch.com. (n.d.). Atorvastatin. Retrieved from <https://www.drugpatentwatch.com/drugs/atorvastatin>