Dyslipidemia is diagnosed in a 34-year-old man. He also has other medical conditions, like a myocardial infarction about a week ago. At the age of 48, his father suffered a myocardial infarction and passed away. Other family members have experienced hypertension and myocardial infarctions. After suffering a myocardial infarction, the patient gave up smoking and drinking. Simvastatin and cholestyramine have been started for him. Which of the following best describes the independent effects of simvastatin and cholestyramine, respectively, on hepatic cholesterol synthesis?

Question

Quizplus · Accepted Answer

Eductional Objective: Bile acid-binding resins, also known as bile acid sequestrants, function by binding bile acids in the gastrointestinal tract. This prevents bile acids from flowing freely through the enterohepatic system and leads to an increase in bile acid excretion. As a result, the liver begins to synthesize new bile acids, using up its stored liver cholesterol in the process. For continuous bile acid synthesis, hepatic absorption of LDL from the blood is enhanced. This disruption of the enterohepatic circulation of bile acids results in a 10-fold increase in bile acid synthesis and secretion. Hepatic cholesterol synthesis is increased as a result of hepatic cholesterol decrease, which activates HMG CoA reductase. This effect can be blocked with the addition of a statin drug to the treatment regimen, leading to a greater reduction in LDL levels than with use of either drug alone (synergistic action).

Dyslipidemia Is Diagnosed in a 34-Year-Old Man