What Are Statins? How Statins Work And The Side Effects Of Statins

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Main Category: Statins
Also Included In: Cholesterol
Article Date: 16 Apr 2009 - 0:00 PST

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Statins are a class of medicines that are frequently used to lower blood cholesterol levels. The drugs are able to block the action of a chemical in the liver that is necessary for making cholesterol. Although cholesterol is necessary for normal cell and body function, very high levels of it can lead to atherosclerosis, a condition where cholesterol-containing plaques build up in arteries and block blood flow. By reducing blood cholesterol levels, statins lower the risk of chest pain (angina), heart attack, and stroke.

Several types of statins exist such as atorvastatin, cerivastatin, fluvastatin, lovastatin, mevastatin, pitavastatin, pravastatin, rosuvastatin, and simvastatin. Atorvastatin and rosuvastatin are the most potent, while fluvastatin is the least potent. These medicines are sold under several different brand names including Lipitor (an atorvastatin), Pravachol (a pravastatin), Crestor (a rosuvastatin), Zocor (a simvastatin), Lescol (a fluvastatin) and Vytorin (a combination of simvastatin and ezetimibe). Mevastatin is a naturally occurring statin that is found in red yeast rice.

How do statins work?

Statins inhibit an enzyme called HMG-CoA reductase, which controls cholesterol production in the liver. The medicines actually act to replace the HMG-CoA that exists in the liver, thereby slowing down the cholesterol production process. Additional enzymes in the liver cell sense that cholesterol production has decreased and respond by creating a protein that leads to an increase in the production of LDL (low density lipoprotein, or "bad" cholesterol) receptors. These receptors relocate to the liver cell membranes and bind to passing LDL and VLDL (very low density lipoprotein). The LDL and VLDL then enter the liver and are digested.

Many people who begin statin treatment do so in order to lower their cholesterol level to less than 5 mmol/l, or by 25-30%. The dosage may be increased if this target is not reached. Treatment with the statin usually continues even after the target cholesterol level is reached in order to sustain atherosclerosis prevention.

Who takes statins?

Statins are usually prescribed to people who have the following conditions:

• Atheroma-related diseases such as heart disease and atherosclerosis. Statins reduce the chance that these conditions will worsen and can delay progression of the diseases.


• Diabetes or another disease that increases the risk of developing an atheroma related disease


• A family history of heart attacks (especially at a young age)


• Increasing age

A high cholesterol level is the most common reason that a person is placed on statins, but the drugs also reduce heart diseases by preventing atherosclerosis. In fact, it is possible to have a heart attack without high blood cholesterol levels, but nearly all heart attacks begin with atherosclerosis plaque buildup. Plaques from atherosclerosis can still form even when blood cholesterol is low. Therefore, statins may be used to treat people who have or are at a higher risk of atherosclerosis even if they do not have high cholesterol levels.

What are side-effects of statins?

Although most people who take statins have minor or no side-effects, many suffer from headache, pins and needles, abdominal pain, bloating, diarrhoea, feeling sick, and a rash. Rarely, patients get a severe form of muscle inflammation.

The only two major side effects - both that occur relatively rarely - are liver failure and skeletal muscle damage. This muscle damage is a severe type of myopathy called rhabdomyolysis. Rhabdomyolysis usually begins as muscle pain and can worsen to where the patient loses muscle cells, experiences kidney failure, or dies. The condition is more common when statins are used in combination with other drugs that carry high rhabdomyolysis risk or with other drugs that raise the statin levels in the blood.

People with active liver disease should not take statins. If liver disease develops while taking statins, usage should be stopped. Also, pregnant and breast-feeding women or those intending to become pregnant should not take statins. It is generally recommended that people taking statins should not combine them with medications such as protease inhibitors (AIDS treatment), erythromycin, itraconazole, clarithromycin, diltiazem, verapamli, or fibrate drugs (that also lower LDL levels).

People who are taking statins should also avoid grapefruits and grapefruit juice due to the dangerous effects of an interaction.

For more information on the harms and benefits of statins, see our article Are Statins Good Or Bad?

Written by Peter Crosta M.A.

Original article date: 13 May 2004
Article updated: 16 April 2009


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