Several drugs are currently available for the treatment of hyperlipidemia, but the most potent agents are known as 3-hydroxy- 3-methylglutaryl-coenzyme (HMG CoA reductase) inhibitors or statins. Statins like Atorvastatin, fluvastatin, lovastatin, Pravastatin, Simvastatin and Rosuvastatin are effective in modifying low-density lipoproteins (LDL), high-density lipoproteins (HDL), total cholesterol (TC) and triglycerides (TG) levels. All agents lower LDL in a dose dependent manner, approximately 20-38% with initial doses and 35- 61% with maximal doses . Statins act by competitively inhibiting HMG-CoA reductase. On a molecular level, statins are similar to HMGCoA occupying the place of HMG-CoA in the enzyme and thereby reduce the rate of mevalonate production which in turn reduces the cholesterol production, as well as a number of other compounds via several mechanisms.
Simvastatin appears to have the ability to reduce low-density lipoprotein cholesterol (LDC-C) and increase HDL cholesterol (HDL-C) to a greater degree than the other approved statins providing a 63% LDL-C reduction at a dose of 40 mg . Simvastatin is also considered as a stimulator for bone formation. Statins are widely prescribed as cholesterol-lowering therapy, and are considered firstline therapeutic agents for the prevention of coronary heart disease and atherosclerotic disorders related to hypercholesterolemia. Statins also have immunomodulatory, neuroprotective and antiinflammatory properties that are being explored for potential benefits in central nervous system disorders .