According to 2006 data presented by the American Heart Association, coronary heart disease is the number one cause of death among Americans, and high cholesterol is one of the principal risk factors for coronary heart disease. This association has led to the widespread use of cholesterol-lowering medications, particularly those belonging to a class of drugs called statins. In 2010, nearly 220 million statin prescriptions were written in the United States. Like all medications, statins have side effects; one of the most worrisome is muscular damage.
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Statins exert their effects on cholesterol synthesis by inhibiting an enzyme called HMG-CoA reductase. This enzyme is present in most of your cells, but it is particularly active in your liver, where most of your body's cholesterol is manufactured. HMG-CoA reductase controls one step of the process that converts fatty acids to cholesterol. By blocking this enzyme, statins interfere with the production of cholesterol and decrease its release into your bloodstream. However, blocking HMG-CoA reductase may have some undesirable effects that contribute to muscle pain.
CoQ10
In addition to participating in the synthesis of cholesterol, HMG-CoA reductase is required for manufacturing coenzyme Q10, or CoQ10. This molecule is intimately involved in the generation of cellular energy, and it protects many cellular components from oxidative damage. Scientists at the Ochsner Clinic Foundation in New Orleans report that statins lower levels of CoQ10 in your serum and muscle tissue, and CoQ10 deficiency might be one cause of statin-induced muscle pain. However, CoQ10 supplementation does not routinely alleviate pain or improve muscle function in patients taking statins.
Transport and Metabolism
Not all people who take statins develop muscle pain. Thus, it is likely that individual differences in the metabolism of these drugs contribute to muscular injury. A May 2011 "Annals of Medicine" review suggests that genetic differences in the transport molecules that carry statins into your liver cells and in the enzymes that metabolize these drugs might lead to differences in statin blood levels among different patients. This could not only account for the muscle pain experienced by some people, but could also explain the variable effectiveness of statins from one person to the next.
Considerations
Statins are among the most widely prescribed medications in the world. They effectively reduce mortality from coronary heart disease, but they are associated with side effects, including significant muscle injury in some patients. Genetic differences in statin metabolism could increase your risk of muscle damage, as could a statin-induced CoQ10 deficiency or combining a statin with other drugs that interfere with its metabolism. If you have muscle pain from a statin medication, you may not necessarily have to stop taking it, and sometimes switching to another statin can alleviate your discomfort. If your cholesterol medication is causing muscle pain, talk to your doctor about your options.
References
- American Heart Association: Cardiovascular Disease Statistics
- "Managed Care Magazine"; Lipitor Kicks off Onslaught of Drug Patent Conversions; T. Reinke; April 2011
- "The Ochsner Journal"; Coenzyme Q10 and Statin-Induced Mitochondrial Dysfunction; R. Deichmann, et al.; Spring 2010
- "Annals of Medicine"; Clinical Response to Statins: Mechanism(s) of Variable Activity and Adverse Effects; C.R. Sirtori, et al.; May 2011
