What are Statins?
Statins are the primary class of lipid lowering medications used to lower serum cholesterol for both primary and secondary prevention of coronary disease. They inhibit the enzyme HMG-CoA reductase which plays a central role in the production of cholesterol. Statin therapy is successful in reducing cholesterol and thus, limiting the incidence of cardiovascular events.
Myalgia, Myositis, Rhabdomyolysis
Statin myopathy is separated into three different types based on toxicity such as myalgia, myositis and rhabdomyolysis. Myalgia refers to generalized pain in the muscles, while myositis presents itself with muscle pain, tenderness, weakness and a higher blood level of creatine kinase. Rhabdomyolysis is an extreme, life threatening type of myopathy. Myalgia can occur with or without serum creatine kinase elevation, a marker for muscle damage. Myositis has a higher level of creatine kinase in the bloodstream. The most extreme, life-threatening type of myopathy, rhabdomyolysis, can display up to 10 times greater creatine kinase levels. This can be fatal due to acute renal failure.
What Causes Statin Myopathy?
The way in which statin myopathy occurs is not well understood. Statins are HMG-CoA reductase inhibitors and prevent the conversion of HMG-CoA to mevalonic acid, an early step in cholesterol biosynthesis. Individual statins may have specific effects on the synthesis of coenzyme Q10, which plays an important role in muscle cell energy production. Conflicting studies have come to different conclusions about whether statins decrease the levels of ubiquinone in skeletal muscle. The jury is still out on what exactly causes statin myopathy adverse effects, but many studies are focusing on additional genes and proteins involved in lipid metabolism. Most statins undergo CYP3A4-mediated biotransformation, and variations in this gene may be responsible for statin muscle myopathy.
Statin Myopathy and Pharmacogenetic Testing
Once the human genome was sequenced, pharmacogenomics emerged in the form of genome wide association studies, which showed that many people have gene variations that are responsible for medication adverse reactions. Testing is available from MD Labs with the Rxight® pharmacogenetic testing. All that is required is a prescription from your physician to see your pharmacist for a cheek swab. The results may be used by you and the prescriber over the lifetime of your individual care, as the test determines your genetic variations with respect to drug metabolism for over 200 drugs.