Cholesterol-lowering drug. 20mg Pills of the cholesterol-lowering drug Simvastatin on a heart shaped background. This drug reduces the levels of low-density lipoprotein (LDL) cholesterol ('bad' cholesterol) in the bloodstream. High levels of LDL cholesterol (hypercholesterolaemia) are a major cause of heart disease and strokes. Simvastatin works by blocking the effects of the enzyme HMG-CoA reductase, which normally causes the body to produce LDL cholesterol from foods.