Rationale: The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, are important drugs used in the treatment and prevention of cardiovascular disease. Although statins are well tolerated, many patients develop myopathy manifesting as muscle aches and pain. Rhabdomyolysis is a rare but severe toxicity of statins. MG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitors, statins, are highly effective drugs for the treatment of hypercholesterolemia, a major risk factor of cardiovascular disease. Statins inhibit the synthesis of mevalonate, the rate-limiting step in cholesterol biosynthesis. 1,2 Although statins are generally well tolerated, 3 skeletal muscle side effects are commonly reported among those treated. One such side effect, myalgia, which is defined as muscle aches or weakness in the absence of blood creatine kinase elevation, occurs in 5% to 15% of statin-treated patients. 2,4 -8 In rare cases, potentially life-threatening statin-induced rhabdomyolysis may occur, a condition characterized by acute muscle damage, resulting in pronounced elevation in creatine kinase levels and possible renal failure. 9 The pathophysiology of statin-induced myopathy is not completely understood. The leading mechanism suggests a role for cellular depletion of secondary metabolic intermediates of mevalonate in the development of statin-induced myotoxicity. 10 In addition to decreased cholesterol synthesis, HMG-CoA reductase inhibition by statins causes a commensurate reduction in the levels of downstream metabolic products including isoprenoids, dolichol, and ubiquinone (coenzyme Q10). 10 -13 Among these are the isoprenoid secondary metabolic intermediates geranylgeranylpyrophosphate and farnesylpyrophosphate that are involved in protein isoprenylation and activation of small GTPases such as Rho and Rab. The important role for diminished isoprenylation in the mechanism of statin myotoxicity is related to induction of the muscle atrophy-linked protein atrogin-1. 12 This is highlighted by the findings that supplementation of geranylgeranylpyrophosphate to cultured skeletal myotubes or isolated myofibers treated with statins leads to attenuation of toxicity, 11,13-15 whereas inactivation of a Rab and RhoA induces toxicity. 11,13 Decreased geranylgeranylation of small GT-