Bile acid sequestrant

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The acid sequestrants bile is a group of resins used to bind certain components of bile in the gastrointestinal tract. They interfere with the enterohepatic circulation of bile acids by combining with bile constituents and preventing their reabsorption from the gut. In general, they are classified as hypolipidemic agents, although they can be used for purposes other than lowering cholesterol. They are used in the treatment of chronic diarrhea due to bile acid malabsorption.

Video Bile acid sequestrant

Mekanisme

Gallbladder sequestrants are polymer compounds that act as ion exchange resins. The sequestran bile acid exchange anions such as chloride ions for bile acids. Thus, they bind bile acids and confiscate them from the enterohepatic circulation. The liver then produces more bile acids to replace the lost ones. Because the body uses cholesterol to make bile acids, it reduces the amount of LDL cholesterol circulating in the blood.

The sequence of bile acids is a large polymeric structure, and they are not significantly absorbed from the intestine into the bloodstream. Thus, bile acid sequestrants, together with bile-linked bile acids, are excreted through the stool after passing through the gastrointestinal tract.

Maps Bile acid sequestrant

Medical use

Hyperlipidemia

As bile acids are synthesized from cholesterol, bile acid reabsorption disorders will lower cholesterol, in particular, low-density lipoprotein (commonly known as "bad cholesterol") in the blood. As a result, these drugs have been used for the treatment of hypercholesterolemia and dyslipidemia.

The use of these agents as hypolipidemic agents has declined markedly since the introduction of statins, which are more efficacious than bile acid sequestrants in lowering LDL. They are sometimes used in addition to statins as an alternative to fibrates (another major group of cholesterol-lowering drugs), which are thought to increase the risk of rhabdomyolysis when used with statins. Bile acid binding resins may raise triglycerides simply (about 5%) and can not be used if triglycerides increase.

Malabsorption of bile acids

Chronic diarrhea can be caused by excess of bile salts entering the colon rather than absorbed in the tip of the small intestine (ileum). The condition of bile acid malabsorption occurs after surgery into the ileum, in Crohn's disease, with a number of other gastrointestinal causes, or is generally a primary, idiopathic condition. SeHCAT tests can be used for diagnosis. Bile salt diarrhea can also be a side effect of gall bladder expenditure.

Gallbladder sequestrants are the main therapies for bile acid-induced diarrhea. Cholestyramine, colestipol and colesevelam have all been used. The dose may not need to be as high as previously used for hyperlipidemia. Many patients find it difficult to tolerate, because although diarrhea may improve, bloating and abdominal pain may worsen.

Use under other conditions

In chronic liver diseases such as cirrhosis, bile acids can settle in the skin, causing pruritus (itching). Therefore, bile acid sequestrants can be used for the prevention of pruritus in patients with chronic liver disease.

Bile acid sequestrants can also be used to treat hyperthyroidism as an adjunctive therapy. By inhibiting enterohepatic circulation, more L-thyroxine will be lost through defecation, thereby lowering the body's thyroxine levels.

Cholestyramine has been used in the treatment of Clostridium difficile infections, to absorb toxins A and B.

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Side effects

As bile acid sequestrants are designed to stay in the intestine, in general, they have no systemic side effects. However, they can cause problems in the digestive tract (digestive tract), such as constipation, diarrhea, bloating and flatulence. Some patients complain of discomfort.

Because bile acid sequestrants are not well absorbed from the intestine, they are generally considered safe in pregnant women. However, by interfering with the absorption of vitamins, they can cause vitamin deficiencies that can affect the fetus. Therefore, vitamin supplements can be considered, with appropriate intervals between the provision of vitamins and bile acid sequestrants.

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Drug interactions

In addition to bile acids, bile acid sequestrants can also bind drugs in the gastrointestinal tract, preventing its absorption into the bloodstream. For this reason, it is generally suggested that bile acid sequestants are spaced several hours apart from other drugs.

They can also bind fat-soluble vitamins, such as vitamin A, vitamin D, vitamin E, and vitamin K. These effects can lead to vitamin deficiency, so checking blood levels and supplementation may have been suggested.

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Example

Three drugs are members of this class; all of them are synthetic polymer resins:

• Cholestyramine (Common names and various names)
• Colestipol (Colestid, Colestipid)
• Colesevelam (Cholestagel in Europe, Welchol in the US, Lodalis in Canada)

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References

Source of the article : Wikipedia