Simvastatin, a long-established treatment for dyslipidemia as monotherapy or in combination with other drugs, is a lactone that, once hydrolyzed, inhibits 3-hydroxy-3-methylglutaryl coenzyme A reductase. At the molecular level, the rate of synthesis of cholesterol depends primarily on the highly regulated activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase.