Pravastatin, molecular model. Pravastatin is a cholesterol-lowering drug of the statin class. It is marketed as Pravachol and Selektine. Statins work by blocking the action of the enzyme, called HMG-CoA reductase, that is responsible for production of cholesterol. Reducing blood cholesterol is important in the prevention of cardiovascular disease. Pravastatin was originally identified in the mould Nocardia autotrophica. In this molecule, atoms are shown as spheres and are colour-coded: carbon (green), oxygen (red) and hydrogen (white).