Bile acid resins are a type of cholesterol-reducing drug. Generally, these medications aim to lower the levels of fats (lipids) in the blood, including cholesterol and triglycerides. Some bile acid resins have been shown to reduce LDL (bad cholesterol) levels by 10 to 20 percent, while simultaneously raising HDL (good cholesterol) levels. High levels of LDL cholesterol, triglycerides and other fats in the bloodstream increase the risk of hardening of the arteries (atherosclerosis), heart attack, stroke and other heart-related conditions.

Bile acid resins may be prescribed in addition to other cholesterol-reducing medications to further reduce LDL levels. Other types of cholesterol reducing drugs include statins, fibrates and nicotinic acid.

Bile acids work by altering the chemistry of cholesterol processing. Under normal circumstances, the liver takes cholesterol out of the blood to make bile, which is used in the intestines during the digestive process. Most of this bile is eventually returned to the liver.  Bile acid resins block the recycling of bile acids in the intestine. To replace the lost bile acids, the liver is forced to remove more cholesterol from the blood to manufacture more bile. Bile acid resins are usually prescribed in powder form (which is mixed with liquid) or in a chewable bar.

Bile acid resins are not absorbed by the body. However, they may interfere with the absorption of some substances, including other medications and some vitamins. Patients are encouraged to inform their physicians of all other over-the-counter or prescription medications they may be taking before beginning bile acid resins therapy. In addition, patients may wish to ask their physicians about taking multivitamins or supplements to replace nutrients that the bile acid resins may prevent from being fully absorbed.

Certain types of bile acid resins (e.g., cholestyramine) are also used to lessen symptoms of patients with liver disease. These medications remove excess bile acids caused by disorders of the liver. The build-up of bile acids can cause symptoms such as severe itching.