What is the primary function of Questran (cholestyramine)?

Cholestyramine, marketed under the brand name Questran, primarily functions as a bile acid sequestrant. Its mechanism involves binding to bile acids in the intestine, which are products of cholesterol metabolism. By binding these bile acids, cholestyramine prevents their reabsorption into the bloodstream. This action prompts the liver to utilize more cholesterol to produce new bile acids, effectively lowering cholesterol levels in the blood.

The role of cholestyramine in managing cholesterol levels highlights its use in treating conditions such as hyperlipidemia. It is particularly effective for lowering LDL cholesterol, which can help reduce the risk of cardiovascular diseases.

The other choices provided do not accurately reflect the primary therapeutic action of cholestyramine. For instance, it does not prevent phosphate absorption, increase HDL levels significantly, or function as a blood thinner. Each of these other functions pertains to different medications or classes of drugs that target specific conditions within the body.