Information about Cholestyramine
Cholestyramine is a nonabsorbed bile acid sequestrant that is used a therapy of hyperlipidemia and for the pruritus of chronic liver disease and biliary obstruction. Cholestyramine has been associated with mild and transient serum enzyme elevations during therapy, but has not been linked to cases of clinically apparent liver injury with jaundice.
Mechanism of action of Cholestyramine
Cholestyramine (koe" le stye' ra meen) is a large, highly positively charged anion exchange resin that binds to negatively charged anions such as bile acids (as well as other organic compounds and some medications). The binding of bile acids to cholestyramine creates an insoluble compound that cannot be reabsorbed and is thus excreted in the feces. Bile acids ordinarily undergo extensive (>95%) enterohepatic recirculation, being secreted in bile, acting as fat solubilizing compounds in the upper intestine, and then being reabsorbed in the distal small bowel. Chronic loss of bile acids from cholestyramine use results in a contraction of the total bile acid pool. The liver compensates for this decrease by increasing bile acid synthesis, which directly competes with cholesterol synthesis resulting in a decrease in serum levels. In addition, cholestyramine may also decrease in serum cholesterol by direct inhibition of fat absorption caused by its binding to bile acids in the intestine.
FDA approval information for Cholestyramine
Cholestyramine was approved for use in the United States in 1973 and is one of the oldest and safest cholesterol lowering agents, but it is currently used largely as an adjunctive therapy when statins or other lipid lowering agents result in an inadequate decrease in cholesterol levels. Cholestyramine is also effective in reducing the pruritus of chronic liver disease, probably as a function of binding the “pruritogen” in the intestine (which is either a bile acid or an organic anion like a bile acid that undergoes enterohepatic circulation). Because cholestyramine binds to negatively charged molecules, it can also be used to reduce absorption of medications taken in toxic overdoses and has multiple drug-drug interactions.
Brand name for Cholestyramine
Cholestyramine is available in multiple generic forms and under the brand name of Questran as a powder or in single dose packet form, generally in 4 gram amounts.
Dosage and administration for Cholestyramine
The usual dose of cholestyramine is 4 grams, given one to six times per day usually before meals and at bedtime. Other drugs should be given 1 hour before or 4 to 6 hours after cholestyramine. Cholestyramine is unpalatable and can be difficult to swallow.
Side effects of Cholestyramine
Side effects include abdominal discomfort, indigestion, nausea, flatulence and constipation.
Lipid lowering medications
- Niacin (Nicotinic Acid)