Statins are a class of medicines that are used to lower blood cholesterol levels. They do this by blocking the action of an enzyme in the liver that is necessary for making cholesterol.

Cholesterol is necessary for normal cell and body function, but very high levels can lead to atherosclerosis, a condition where cholesterol-containing plaques build up in the arteries and block blood flow.

By reducing blood cholesterol levels, statins lower the risk of chest pain (angina), heart attack, and stroke. Here we will look at how statins work, who uses them, and the associated risks and benefits.

Fast facts on statins:

  • Statins are used to lower cholesterol levels in the blood.
  • Statins work by inhibiting an enzyme called HMG-CoA reductase.
  • People with atheroma-related disease, diabetes, and a family history of heart attacks are often prescribed statins.
  • People with liver disease should discuss the risks and benefits of statins carefully with their doctor.

Statins are a type of medication that blocks the action of a liver enzyme that helps produce cholesterol. They are typically prescribed to lower blood cholesterol levels. Types of statins include:

Atorvastatin and rosuvastatin are the most potent, while fluvastatin is the least potent. These medicines are sold under several different brand names, including:

  • Lipitor (atorvastatin)
  • Pravachol (pravastatin)
  • Crestor (rosuvastatin)
  • Zocor (simvastatin)
  • Lescol (fluvastatin)
  • Vytorin (a combination of simvastatin and ezetimibe)

Most people who take statins have minor or no side effects. Minor side effects include:

  • headache
  • pins and needles sensation
  • abdominal pain
  • bloating
  • diarrhea
  • feeling sick
  • a rash

Some statin drugs may impair memory – researchers at the University of Bristol in England found that two commonly prescribed statins – pravastatin (Pravachol) and atorvastatin (Lipitor) – reduced performance of recognition and working memory in an animal study.

Statins may also raise the risk of developing cataracts. A research team at the San Antonio Military Medical Center, TX, reported in JAMA Ophthalmology that statin usage increased the risk of cataracts by 27 percent.

The two most serious side effects – both of which occur relatively rarely – are liver failure and skeletal muscle damage.

The muscle damage typically presents as muscle pain, which is often relieved when switching to a different type of statin. In rare cases, a severe type of myopathy called rhabdomyolysis may occur.

What is rhabdomyolysis?

Rhabdomyolysis begins as muscle pain and can worsen to the extent that the patient experiences significant muscle breakdown, 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.

Who should not take statins?

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Pregnant women are among those who should not take statins.

People with liver disease should speak with their doctor carefully about the risks and benefits before starting a statin. If liver disease is stable and chronic, a low dose statin may have greater benefit than risk.

If liver disease is progressive, statins are not advised.

If liver disease develops while taking statins,a discussion with your doctor is warranted to determine dose reduction, change in medication or stopping statin use altogether.

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 the following medications:

  • protease inhibitors (AIDS treatment)
  • erythromycin
  • itraconazole
  • clarithromycin
  • diltiazem
  • verapamil
  • fibrate drugs (that also lower LDL levels)

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

Statins inhibit an enzyme called HMG-CoA reductase, which controls cholesterol production in the liver. The medicine blocks the enzyme, thereby slowing down the cholesterol production process.

People often begin statin treatment to lower their cholesterol level to below 5 millimoles per liter (mmol/L), or by 30-60 percent. The dosage may be increased if this target is not reached.

Treatment with statins usually continues even after the target cholesterol level is reached to continue the protection against atherosclerosis.

Statins may be prescribed in the following cases:

  • Atheroma-related diseases such as heart disease, stroke and atherosclerosis.
  • Diabetes which increases the risk of developing an atheroma-related disease.
  • Elevated LDL cholesterol levels at 190 milligrams per decilter (mg/dL) or higher.
  • 10-year risk of cardiovascular disease at 7.5 percent or higher.

A high cholesterol level is the most common reason that a person is prescribed statins, but the drugs also reduce heart diseases risk by preventing atherosclerosis.

Plaques from atherosclerosis can still form even when blood cholesterol is low. Therefore, statins may be used to treat people who already have atherosclerosis or are at a higher risk of developing it, even if they do not have high cholesterol levels.

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