Statin medications are part of a larger group of medications known as lipid-altering agents--they change the levels of fat and cholesterol in the blood. Statin drugs prevent the enzyme HMG CoA reductase from working properly. Without this enzyme, cholesterol cannot be made in the liver. This action results in the advantages associated with the statin medications.
Significance
The American Heart Association estimates that more than 100 million people in the United States have high cholesterol, defined as a total cholesterol level of over 200 milligrams per deciliter. Even more alarming is the fact that about 37 million of these men and women have extremely high cholesterol levels, indicated by a total cholesterol level of more than 240 milligrams per deciliter. Since elevated levels of cholesterol are directly linked to the risk for heart disease, strokes and heart attacks, the ability to lower the levels of cholesterol in the blood can have a major impact on patients' lives.
Features of Statins
There are seven statin medications available as of 2010: simvastatin, rosuvastatin, pravastatin, pitavastatin, lovastatin, atorvastatin, and fluvastatin. While they all have the same basic mechanism of action, they are not identical medications. For instance, some statins, such as rosuvastatin, are more powerful in their ability to lower levels of LDL, or bad, cholesterol. Other statins, such as atorvastatin, are more effective in lowering fat, or triglyceride, levels.
Still other statins may not be quite as powerful in terms of how much they can lower cholesterol levels but have the advantage of fewer side effects. For instance, fluvastatin has been noted to have fewer muscle-related side effects, as was found in a 2005 study that included over 7,000 patients. The advantage of these slight differences is that patients can be put on a statin that would be most beneficial to their specific problems.
Benefits and Advantages
Statin therapy has been found to have several major benefits, including the benefit of greatly lowering the levels of LDL cholesterol. Robert Rosenson, M.D., of the Mount Sinai School of Medicine summarizes a handful of older studies that were done on statin therapy and reports that the LDL-lowering effect ranges from a decrease of 30 percent to over 60 percent.
Another advantage to statin medication is that there is a potential for increasing HDL--the so-called "good" cholesterol--by up to 10 percent. This was found in a 2003 study comparing several types of statins: the authors found that in patients taking rosuvastatin, HDL cholesterol levels went up by nearly 10 percent.
Another positive effect of statin therapy is that of lowering triglycerides, or fats, in the blood. This is especially true of atorvastatin and rosuvastatin. The 2003 study comparing rosuvastatin, atorvastatin, simvastatin and pravastatin found that triglyceride levels may go down by as much as 33 percent.
Other Advantages
The AFCAPS/TexCAPS study found that men and women with cholesterol levels considered to be within the normal range could benefit from statin therapy. This landmark study included over 5,000 men and nearly 1,000 women with normal levels of total cholesterol. The authors found that after five years of therapy with either a statin or an inactive "placebo" drug, the patients receiving statin therapy had fewer heart attacks and fewer sudden deaths for heart-related reasons. The LDL cholesterol levels of the patients receiving statins also decreased significantly. The conclusion drawn by the authors of the study was that statin therapy can benefit even people whose cholesterol levels are within normal range.
Side Effects
Despite the advantages associated with statin therapy, the side effects of these medications should also be taken into consideration. Dr. Rosenson reports that statins, in comparison with other lipid-altering agents, have fewer side effects.
Liver dysfunction is one possible side effect--a 2006 review of 35 major studies found that patients are at increased risk for having elevated liver enzymes. Other possible side effects include the potential for muscle damage which results in temporary muscle pain and weakness; kidney damage; and behavioral changes such as irritability and aggression. Dr. Rosenson emphasizes that this last side effect is especially rare. Finally, it is not yet known if statin therapy is harmful to a fetus.
References
- American Heart Association: Cholesterol Statistics
- "Cardiovascular Drugs and Therapy;" Mild to moderate muscular symptoms with high-dosage statin therapy in hyperlipidemic patients--the PRIMO study; E. Bruckert et. al.; December 2005
- "American Journal of Cardiology;" Comparison of the efficacy and safety of rosuvastatin versus atorvastatin, simvastatin, and pravastatin across doses (STELLAR* Trial); P.H. Jones et. al.; July 2003
- "Journal of the American Medical Association;" Primary prevention of acute coronary events with lovastatin in men and women with average cholesterol levels: results of AFCAPS/TexCAPS. Air Force/Texas Coronary Atherosclerosis Prevention Study; J.R. Downs et. al.; May 1998
- "Circulation;" Risks associated with statin therapy: a systematic overview of randomized clinical trials; A. Kashani et. al.; December 2006
