Your Cholesterol Profile - In Depth (cont.)
What are the statin drugs?
The statins are the most widely used, and also the most powerful medications
for lowering LDL cholesterol. Numerous large, randomized, double-blind,
placebo-controlled, , clinical trials (controlled trials) have shown that
statins reduce heart attacks (and strokes) and improve survival. Statins are
well tolerated with low side effect rates when used long term. Statins not only
lower blood LDL cholesterol levels, they also modestly increase HDL cholesterol
levels and modestly decrease triglyceride levels. The statins that are now on
pharmacy shelves in the U.S. (putting the generic name first followed by the
brand name in parentheses) are:
- rosuvastatin
( Crestor)
- fluvastatin sodium (Lescol) made by
Novartis
- atorvastatin calcium (Lipitor) made by Parke-Davis
and Pfizer
- lovastatin (Mevacor) made by Merck
- pravastatin sodium (Pravachol) made by Bristol-Myers
Squibb
- simvastatin (Zocor) made by Merck
The statins act by repressing or inhibiting an enzyme called HMG-CoA
reductase. The role of this enzyme is the promotion of a chemical reaction early
in the production (synthesis) of cholesterol. By inhibiting HMG-CoA reductase,
the statins hinder the production of cholesterol by the liver. The diminished
synthesis of cholesterol in the liver in turn stimulates (increases) the
activity of LDL receptors on the surface of liver cells. Increasing LDL receptor
activity decreases LDL cholesterol levels in blood.
Studies have consistently shown that lowering LDL cholesterol with diet and
statins reduces the risk of a second heart attack. The prevention of recurrent
heart attacks in patients who have already suffered a heart attack is called
secondary prevention.
Studies have also demonstrated that reducing LDL cholesterol with lifestyle
changes and statins reduces the risk of having the first heart attack.
Prevention of heart attacks in those who have never had a heart attack is called
primary prevention.
Studies have also confirmed that reducing LDL cholesterol benefits both men
and women, and the elderly.
What are side effects of statins?
Statins are generally well tolerated and side effects are rare. The most
common side effects are headache, nausea, vomiting, constipation, diarrhea,
headache, rash, weakness, and muscle pain.
Statins can cause muscle injury,
ranging from myalgias (muscle pain), myositis (muscle inflammation), to
rhabdomyolysis (death of muscle cells that can lead to kidney failure). Myalgias
can occur at a frequency of 2%-10%, and will resolve upon discontinuing the
statins. The more serious rhabdomyolysis fortunately is rare, occurring at a
frequency of less than 0.1%. It occurs more often when statins are used in
combination with other drugs that themselves cause rhabdomyolysis (example;
gemfibrozil), or with drugs that prevent the elimination of statins and raise
the levels of statins in the blood (for example; cyclosporine, verapamil,
erythromycin, ketoconazole, amiodarone, or one quart daily of grapefruit juice).
Rhabdomyolysis often begins as muscle pain and then progresses to cause kidney
damage. Therefore, unexplained joint or muscle pain that occurs while taking
statins should be brought to the attention of a doctor.
Clinical studies have found elevations in blood levels of liver enzymes
(aminotransferases; ALT and AST) at a frequency of 0.5% to 3%. But in several
large controlled trials, scientists found no difference in the incidence of
abnormal liver enzymes between statin users and subjects taking a placebo. Thus,
scientists cannot attribute abnormal liver enzymes to statin use.
Nevertheless, as a precaution, the United States FDA labeling information
advises that liver enzyme blood tests be performed before and at 12 weeks
following the initiation of statin treatment or elevation of dose, and
periodically thereafter (for example, every 6 months).
In patients with existing liver diseases or with abnormal liver blood tests
at baseline (before initiating statin treatment), measures can be taken to
minimize potential aggravation of liver disease. For instance, using statins
that theoretically have little effect on the liver, such as pravastatin
(Pravachol) or rosuvastatin (Crestor), in low doses, can be used. Liver enzyme
blood tests can also be regularly monitored during statin treatment.
For more information regarding the side effects, precautions, and drug
interactions of the various statins, please read the article on
Statins.
When do doctors prescribe a statin drug?
Decisions regarding when to initiate a statin drug, the choice of statin
medication, and whether to use a statin in combination with another lipid
altering drug, have to be individualized after consulting the doctor.
Therapeutic lifestyle changes (discussed above) should be advised for all
patients in need of lowering LDL cholesterol and; medications are prescribed
when lifestyle changes are insufficient.
Increasingly, doctors are using a statin or a statin in combination with
another lipid-altering drug for secondary prevention (prevention of a second or
third heart attack), for patients who have diabetes, or patients who are at high
risk for heart attacks. Lifestyle changes alone are often insufficient to
achieve the NCEP recommended LDL cholesterol targets for these high risk
patients.
Increasingly, doctors are also prescribing a statin for primary prevention
(prevention of a first heart attack). The decision whether to use a statin for
primary prevention must be individualized, weighing the risks and the benefits.
Doctors are more likely to recommend a statin for primary prevention if a person
has risk factors for coronary heart disease and lifestyle changes implemented by
the patient has not lowered LDL cholesterol sufficiently to desired levels (see
the NCEP recommendations above).
How do doctors select statin drugs?
Which statin to use is an individualized decision. There are several
considerations in choosing a statin:
- In patients who need intense LDL
cholesterol-lowering, it is more appropriate to use one of the more potent
statins, such as atorvastatin (Lipitor) or rosuvastatin (Crestor). Sometimes a
statin may need to be combined with another medication such as cholestyramine
(Questran), ezetimide (Zetia) or nicotinic acid, in order to achieve the LDL
cholesterol goals.
- In patients with chronic liver disease who need
statin treatment, it is important to completely abstain from alcohol and use
either pravastatin (Pravachol) or rosuvastatin (Crestor) in low doses.
(Pravastatin and rsuvastatin are safer to use in patients with liver disease.)
If LDL cholesterol goals cannot be attained with low doses of either of these
two statins, cholestyramine (Quesetran) or ezetimide (Zetia) can be added.
- In patients who develop muscle aches or muscle damage
with a statin, it may be appropriate to try another statin, such as
pravastatin (Pravachol), that probably has less of a muscle toxic effect than
the other statins. In patients who are at risk of developing muscle injury
(for example a patient who is already taking gemfibrozil), pravastatin
(Pravachol) would also be a suitable statin to use.
- Atorvastatin (Lipitor) and fluvastatin
(Lescol) do not require dose adjustments in patients with kidney diseases.
Next: What is nicotinic acid? »
- Statins - Read about statins, cholesterol lowering medications like Levacor, Zocor, Pravachol, Lipitor, Crestor, and more. Side effects, drug interactions, and patient information is also provided.
- Electrocardiogram (ECG or EKG) - Read about the Electrocardiogram (ECG, EKG) procedure used to reflect underlying heart conditions such as agnina, occurance of a prior heart attack or of an evolving heart attack, and more.
- Heart Attack - Overview on heart attack (myocardial infarction) and heart attack symptoms including jaw pain, headache, shortness of breath, nausea, vomiting, heartburn, sweating, and more.
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