This drug is indicated for hyperlipidemia, which refers to abnormally high levels of lipids or lipoproteins in the blood. Bile acid resins are also indicated for familial hyperlipidemia type IIa, an inherited disease where patients display xanthelasmas, arcus senilis, and tendon xanthomas.
This drug is a bile acid sequesterant, which binds to bile acids in the gastrointestinal tract. These form insoluble complexes which are excreted in the feces.
Bile acid sequestrants promote apoprotein A1 synthesis by an unknown mechanism and tend to slightly raise high-density lipoprotein (HDL) cholesterol levels. These drugs also activate phosphatidic acid phosphatase, which promotes hepatic triglyceride (TG) synthesis and slightly raises their levels.
As bile is sequestered and excreted, the liver has to use cholesterol to make more bile. Intracellular cholesterol depletion leads to upregulate expression of HMG-CoA reductase and LDL reductase. This results in increased uptake of LDL particles by hepatocytes and subsequent reduction in plasma LDL.
Colestipol is a bile acid resin which is commonly used. It has been known to bind to other medications and decrease their absorption/mechanism of action, such as digoxin, lasix and tetracycline.
Cholestyramine is a commonly used bile acid resin, which is also used in other diseases. This drug can be used in Crohn's patients who have undergone ileal resection to prevent diarrhea. Furthermore, cholestyramine can be used to absorb toxins during a C. Difficile infection.
Colesevelam is another commonly used bile acid resin, which also has been used to improve glycemic control in type II diabetics.
Very rarely, bile acid sequesterants can lead to cholesterol gallstones. This is because treatment yields higher cholesterol concentrations in the bile.
Use of these medications lead to decreased absorption of fat-soluble vitamins: Vitamins A, D, E and K.
Patients tend to dislike these drugs for treating their hyperlipidemia. They taste bad and lead to GI discomfort.
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