Statins (or HMG-CoA reductase inhibitors) are a class of cholesterol lowering drugs that inhibit the enzyme HMG-CoA reductase which plays a central role in the production of cholesterol. High cholesterol levels have been associated with cardiovascular disease (CVD). Statins have been found to reduce cardiovascular disease and mortality in those who are at high risk. The evidence is strong that statins are effective for treating CVD in the early stages of a disease (secondary prevention) and in those at elevated risk but without CVD (primary prevention). Side effects of statins include muscle pain, increased risk of diabetes mellitus, and abnormalities in liver enzyme tests. Additionally, they have rare but severe adverse effects, particularly muscle damage.