Simvastatin: a Review

Simvastatin is a long-established hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, first introduced in 1988. At the maximal recommended dose of 80 mg/day, it produces an average reduction in low-density lipoprotein cholesterol (LDL-C) of 47%, accompanied by reductions in very LDL-C, triglycerides and apolipoprotein B, and a modest increase in high-density lipoprotein cholesterol. The only important, although rare, adverse effect of simvastatin is myopathy, an effect shared by all members of the class; when severe, this can take the form of rhabdomyolysis, which may lead to acute renal failure. The mechanism of the myopathy is not understood. The risk is increased by certain concomitant drugs, including gemfibrozil and potent inhibitors of cytochrome P450 3A4. Simvastatin has been studied in two large outcome trials, the Scandinavian Simvastatin Survival Study (4S), and the Heart Protection Study (HPS), both of which demonstrated strikingly beneficial effects on a variety of cardiovascular outcomes, with minimal adverse effects. 4S was the first study with a cholesterol-lowering agent to demonstrate an unequivocal reduction in all-cause mortality (30%; p = 0.0003). HPS showed that the beneficial effects of simvastatin were obtainable in a broad array of patients with, or at high risk of, coronary heart disease (CHD) in categories previously little studied, including women, the elderly, patients with diabetes without known CHD, and, perhaps most importantly, patients with LDL-C well below the UK population average. Simvastatin has recently become available in many countries as a combination product with the cholesterol absorption inhibitor, ezetimibe. Because of its long record of safety and demonstrated ability to reduce cardiovascular risk, simvastatin has recently become available without a prescription in the UK at the 10 mg dosage level.