Question

Which drug binds bile acids in the intestine and prevents their return to the liver via the enterohepatic circulation?

• A. Niacin
• B. Fenofibrate
• C. Cholestyramine
• D. Gugulipid

Hint:

Think of the non-absorbable resin that traps bile salts in the gut.

Answer 1

The Correct Option is C

Step 1: The question describes a bile acid sequestrant (also called a bile acid binding resin). These drugs are large, non-absorbable anion exchange resins that bind negatively charged bile acids in the gut lumen.

Step 2: Cholestyramine binds bile acids in the intestine and prevents their reabsorption in the terminal ileum, so the bile acids are excreted in the faeces. This interrupts the enterohepatic circulation of bile acids.

Step 3: Loss of bile acids forces the liver to convert more cholesterol into new bile acids. To do this, hepatocytes upregulate LDL receptors and pull more LDL cholesterol out of the blood, lowering plasma LDL.

Step 4: The distractors act elsewhere. Niacin reduces hepatic VLDL secretion and lowers lipolysis in fat tissue. Fenofibrate is a PPAR-alpha agonist that mainly lowers triglycerides. Gugulipid is a herbal lipid lowering agent. None of these bind bile acids in the gut, so the answer is Cholestyramine.