Statins
With more and more research finding that statins lower the risk of heart attack and stroke, physicians are prescribing these drugs more than ever. But there has been some question as to whether or not statins can cause liver damage.
Statins and Cholesterol
Despite its bad reputation, cholesterol is a necessary substance in the human body. It is one of the building blocks for cell membranes, hormones and bile. Although some cholesterol is obtained through the diet, the liver also manufactures cholesterol from other substances.
Statin is the common name for a class of drugs known as HMG-CoA Reductase Inhibitors. HMG-CoA is an enzyme in the liver necessary for the manufacture of cholesterol. Statins work by blocking the action of this enzyme. When the liver is unable to make cholesterol, it pulls more cholesterol out of the blood stream. This drops the level of total cholesterol and decreases the amount of LDL, or "bad" cholesterol.
The Liver
Cholesterol is transported through the body in particles called lipoproteins. Low-density lipoproteins (LDL) are the "bad" cholesterol. Although LDL carries cholesterol to the places it is needed in the body, extra LDL can form plagues on the walls of blood vessels. These plagues can cause blockages and eventually lead to heart attack and stroke. High-density lipoproteins are the "good" cholesterol. HDL gathers the excess LDL and carries it back to the liver, potentially leading to liver problems.
Significance
Your doctor can test to see if statins are causing liver problems by checking your liver enzymes. Liver cells contain certain enzymes that are essential to its proper functioning. When liver cells are damaged, those enzymes are released into the blood stream. Elevated liver enzymes indicate that liver damage has occurred.
About two percent of people who take statin drugs will have elevated liver enzymes. People who are taking other drugs that are hard on the liver and those who drink a significant amount of alcohol are more likely to have elevated liver enzymes while taking a statin. Once the person is taken off the statin drugs, the liver enzymes generally return to normal within a few weeks, and no permanent liver damage occurs.
Permanent liver damage due to statins is rare. In the many large-scale clinical trials on the statin drugs, no case of permanent liver damage due to statin use was seen.
Considerations
Your doctor should test your liver enzymes before you start taking a statin. People who already have liver problems should not take statin drugs. When elevated liver enzymes occur while taking a statin, lowering the dose of the statin drug is often enough to return the levels to normal. Some people who have elevated liver enzymes with one statin drug find that another drug in the statin family does not affect their liver enzyme levels.
References
- Cardiovascular Therapeutics; Elliott Antman; 2006
- Conn's Current Therapy; Robert E. Rakel and Edward T. Bope; 2009
- Basic and Clinical Pharmacology; Bertram Katzung; 2007
