Statin Drugs: Not Just for High Cholesterol?
Heart disease is the leading killer of Americans, and cholesterol plays a major role in the development of heart disease. Fortunately, statin drugs are helping thousands of people control their cholesterol.
Research has also suggested that statin drugs may be effective in lowering the risk of strokes. In a recent clinical trial of daily atorvastatin after recent stroke or "mini-stroke" (and no known coronary heart disease), atorvastatin reduced the risk of repeat stroke or heart attack.* And other evidence suggests that statins may eventually have a role in the treatment or prevention of osteoporosis and Alzheimer's disease. But statins may also cause serious problems for some patients; while other drugs, as well as diet and exercise, can lead to health benefits without potential statin risks.
How Do Statins Work?
Statins have been used primarily to treat high blood cholesterol. High levels of low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol) especially when accompanied by low levels of high-density lipoprotein (HDL) cholesterol (the "good" kind) can lead to atherosclerosis (clogged arteries), which is the primary cause of coronary heart disease and heart attacks. And, while not the primary cause, atherosclerosis can contribute to strokes, explains Jacques Carter, MD, MPH, of Boston's Beth Israel Deaconess Medical Center.
Statin drugs, which include atorvastatin (Lipitor), pravastatin (Pravachol), lovastatin (Mevacor), simvastatin (Zocor), and fluvastatin (Lescol), work by inhibiting a liver enzyme (called "HMG CoA reductase") that is involved in the production of cholesterol. They are most effective at lowering levels of LDL cholesterol and are somewhat effective at increasing levels of HDL cholesterol.
Statins have become the most popular cholesterol-lowering drugs, because they are highly effective and generally well-tolerated.
Statins Reduce Health Risks
Statins have been shown to help prevent first heart attacks as well as recurrent heart attacks. In addition, data gathered from numerous clinical trials conducted over a 10-year period have demonstrated that in addition to significantly reducing the risk of coronary heart disease and heart attacks, statin drugs may also significantly reduce the risk of dying from a stroke.
Statins and Alzheimer's Disease
At the annual meeting of the Society for Neuroscience in November 1999, Ben Wolozin, MD, PhD, of Loyola University Medical Center in Chicago, presented the results of a study examining the rates of Alzheimer's disease among 50,000 patients. His findings indicate that some statin drugs (lovastatin and pravastatin) may delay or prevent the onset of Alzheimer's disease. However, other studies have not yet confirmed these findings, and additional research is needed to verify this potential effect of statin drugs.
Statins and Osteoporosis
A study published in The Lancet in 2000 suggested that statin drugs may favorably affect bone density in patients at risk for osteoporosis. The study showed that women over age 60 who took statin drugs had a 50% lower risk of bone fractures. However, another study, published in the Journal of the American Medical Association in 2001, failed to show reduced fracture rates with commonly prescribed doses of statins. More research is needed before statins are routinely prescribed for this purpose.
Are Statin Drugs Safe?
Thus far, statin drugs as a class appear to be acceptably safe, even though at least one statin has been withdrawn from the market because of potentially dangerous muscle damage. Some potential side effects include:
Initially, there was concern that statin drugs could harm the liver. To date, it appears that this is generally not the case. Nevertheless, as a precaution, most physicians test their patients' blood prior to and periodically during treatment to be sure the liver is healthy and remains that way. In the vast majority of cases, any abnormalities that develop are completely reversed once the drug is discontinued.
Muscle Pain or Weakness
Rarely, patients may develop serious inflammation of the muscles, which is also reversible when the medication is discontinued. All patients taking statin drugs are warned of this potential complication and directed to immediately stop taking the drug and contact their doctor if they experience muscle pain, weakness, or flu-like symptoms. If muscle damage continues, release of muscle substances into the bloodstream can lead to serious or even permanent kidney damage.
Despite initial animal studies suggesting increased cancer risk, studies among humans have shown no significant increase in the incidence of cancer in people taking these drugs. This conclusion was reinforced by a 2005 study involving over 90,000 patients and showing no cancer excess.
Heart Information Network
Heart and Stroke Foundation of Canada
Baigent C, Keech A, Kearney PM, et al. Cholesterol Treatment Trialists' (CTT) Collaborators. Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90,056 participants in 14 randomised trials of statins. Lancet. 2005;366:1267-1278.
Chan KA, Andrade SE, et al. Inhibitors of hydroxymethylglutaryl-coenzyme A reductase and risk of fracture among older women. Lancet. 2000;355:2185-2188.
Jick H, Zomberg GL, Jick SS, et al. Statins and the risk of dementia. Lancet. 2000;356:1627-1631.
Wegman S, deVries F, Leufkens B, et al. Use of statins and risk of fractures. JAMA. 2001;285:1850-1855.
Wolozin B, Kellman W, Rousseau P, et al. Decreased prevalence of Alzheimer's disease associated with 3-hydroxy-3-methyglutaryl coenzyme A reductase inhibitors. Arch Neurol. 2000;57:1439-1443.
*Updated on 9/19/06 according to the following study, as cited by DynaMed's Systematic Literature Surveillance: Amarenco P, Bogousslavsky J, Callahan A 3rd, et al. High-dose atorvastatin after stroke or transient ischemic attack. N Engl J Med. 2006;355:549-59.
Last reviewed July 2007 by Craig Clark, DO, FACC, FAHA, FASE
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