Simvastatin is used to lower levels of cholesterol and other fats in the blood. This may help prevent medical problems caused by cholesterol clogging the blood vessels. This medication belong to the group of medicines called 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors. They work by blocking an enzyme that is needed by the body to make cholesterol. Thus, less cholesterol is made.