Cholesterol (cont.)
What are fibric acid derivatives (fibrates)?
Fibric acid derivatives (fibrates) are effective medications in lowering blood
triglyceride levels. Fibrates lower blood triglyceride levels by inhibiting the
liver production of VLDL (the triglyceride-rich lip-protein fraction), and by
speeding up the removal of triglycerides from the blood. Fibrates are also
modestly effective in increasing blood HDL cholesterol levels. However, fibrates
are not effective in lowering LDL cholesterol. Examples of fibrates available in
the United Sates include Gemfibrozil (Lopid) and fenofibrate (Tricor).
Very high triglyceride levels (usually > 1000 mg/dl) can cause
pancreatitis
(inflammation of the pancreas that can result in a serious an illness with
severe abdominal pain). By lowering the blood
triglycerides, fibrates are used to
prevent pancreatitis.
Fibrates are not effective in lowering LDL cholesterol and cannot be used
alone in lowering LDL cholesterol levels. However, when a high risk patient (see
NCEP recommendations above) also has high blood triglyceride or low HDL
cholesterol levels, doctors may consider combining a fibrate, such as
fenofibrate (Tricor), with a statin. Such a combination will not only lower the
LDL cholesterol, but will also lower blood triglycerides and increase HDL
cholesterol levels.
Fibrates have also been used alone to prevent heart attacks especially in
patients with elevated blood triglycerides and low HDL cholesterol levels. In
one large study, gemfibrozil decreased the risk of heart attacks but did not
affect the overall survival of persons with high cholesterol levels. For more,
please read our article on Fibrates.
What are bile acid sequestrants?
Bile acid sequestrants such as Cholestyramine (Questran),
colestipol
(Colestid), and colesevelam (Welchol) are medications for lowering LDL
cholesterol. Bile acid sequestrants bind bile acids in the intestine and cause
more of the bile acids to be excreted in the stool. This reduces the amount of
bile acids returning to the liver and forces the liver to produce more bile
acids to replace the bile acids lost in the stool. In order to produce more bile
acids, the liver converts more cholesterol into bile acids, which lowers the
level of cholesterol in the blood.
Bile acid sequestrants have modest LDL cholesterol-lowering effects. Low
doses (for example 8 gram/day of Cholestyramine) can lower LDL cholesterol by
10%-15 %. But even high doses (24 gram/day of cholestyramine) can only lower LDL
cholesterol by approximately 25%. Therefore, bile acid sequestrants used alone
are not as effective as statins in lowering LDL cholesterol.
However, bile acid sequestrants are most useful in combining with a statin or
niacin to aggressively lower LDL cholesterol levels. The statin-bile acid
sequestrant combination can lower LDL cholesterol levels by approximately 50%,
lower than a statin alone. A statin-niacin combination can substantially reduce
LDL cholesterol and elevate HDL cholesterol. For more, please read our article
on Bile Acid Sequestrants.
Next: What is ezetimibe (Zetia)? »
- 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.
- Homocysteine - Read about the test for homocysteine levels in the blood. High levesl of homocysteine include increased risk of heart attacks, strokes, blood clots, and Alzheimer's disease.
- Diabetes - Learn about type 1 and 2 diabetes (Diabetes Mellitus) symptoms including increased urination, thirst, weight loss, fatigue, nausea, vomiting, skin infections, and blurred vision. Causes and diagnosis information is provided in the information.
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