Pravastatin is part of a group of cholesterol-lowering drugs called HMG-CoA reductase inhibitors. This means that pravastatin, and other drugs in its class, work in a similar way: they inhibit, or block, an enzyme called HMG-CoA reductase. The enzyme HMG-CoA reductase is needed to help the liver produce cholesterol. When this enzyme is blocked, cholesterol production in the body still happens, but it happens much more slowly than usual. This results in lower levels of cholesterol in your blood.