Help me understand my cholesterol drugs

Conditions Expert Dr. Otis Brawley Chief Medical Officer,
American Cancer Society

Expert answer

The liver function tests are a group of a dozen or so chemicals measured in the blood. Taken together they can indicate the condition of the liver. Some are elevated in certain types of liver disease, some are low in certain types of liver disease. Many drugs and especially alcohol are common causes of elevation of liver enzymes called aminotransferases. Some cholesterol-lowering drugs can also cause elevation of aminotransferases. Abnormal liver function is found in nearly 10 percent of patients tested. Because so many things can cause abnormal liver function, it may be necessary to start and stop a cholesterol-lowering drug several times while conducting the tests to see whether it is the cause of the problem. Besides other drugs, other very common reasons for liver enzyme elevation include:

• Viral hepatitis with hepatitis B, C or delta

• Fatty liver disease, also known as steatohepatitis

• Hereditary hemochromatosis, a common problem causing iron overload

• Wilson's disease, which involves a buildup of copper in the liver

• Alpha-1 antitrypsin deficiency, an inherited disorder which in severe form is associated with an emphysema similar to lung disease

• Autoimmune hepatitis (a rheumatologic disease)

High cholesterol levels increase risk of heart attack and other vascular diseases. Someone with high cholesterol may benefit from dietary counseling, preferably by a dietitian, along with weight control and exercise. Many will need a lipid-lowering drug in addition. These agents fall into several classes that include statins, fibric acid derivatives, bile acid sequestrants, nicotinic acid (also known as niacin) and the cholesterol absorption inhibitors. These drugs differ in how they work and the degree and type of the lipid they lower.

Physicians usually prescribe a drug based on the underlying lipid abnormality. The most common type of cholesterol problem is a high LDL (low density lipoprotein) which is usually best treated with a statin, of which there are at least four on the market. When a patient cannot tolerate any statin, reasonable options include the use of ezetimibe (trade name Zetia); bile acid sequestrants; fenofibrate, which inhibits liver enzymes; and niacin. Referral to a lipid specialist is also very appropriate in such patients.

In answer to your question, Ezetimibe (trade name Zetia) is a cholesterol absorption inhibitor. It prevents cholesterol ingested in the diet from being absorbed into the body. It modestly lowers the blood LDL cholesterol when used alone. It may be helpful for avoiding high doses of statins in patients who do not meet cholesterol goals on low dose statin therapy alone. The clinical benefits of either ezetimibe alone or combining ezetimibe with statin therapy have recently come into question. A recent study of ezetimibe and the statin simvastatin (trade name Zocor) failed to show that the combination was better than simvastatin alone in avoiding cholesterol-related disease even though it lowered cholesterol levels. The combination of ezetimibe and simbastatin is marketed under the name Vytorin. These results are preliminary and no one should stop these drugs without counsel from their physician.