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Pharmacology · patient case question

What is the mechanism of action of the statins?

Patient case: Bone biology and drug mechanisms

Scenario: One histology item followed by a run of mechanism-of-action questions.

  1. Activate lipoprotein lipase to clear triglycerides
  2. Bind bile acids in the gut and prevent their reabsorption
  3. Block intestinal absorption of dietary cholesterol
  4. Inhibit HMG-CoA reductase, reducing hepatic cholesterol synthesis
Show answer and explanation

Correct answer: D. Inhibit HMG-CoA reductase, reducing hepatic cholesterol synthesis

  • A. Fibrates act through PPAR-alpha to raise lipoprotein lipase activity and lower triglycerides.
  • B. Bile acid sequestrants such as cholestyramine work that way — a different class.
  • C. Ezetimibe blocks intestinal cholesterol absorption at the NPC1L1 transporter.
  • D. Correct. Statins competitively inhibit HMG-CoA reductase, the rate-limiting enzyme of hepatic cholesterol synthesis. The liver responds by upregulating LDL receptors, clearing LDL from the blood.

Note: The dental relevance: statins carry a risk of myopathy, and that risk rises with drugs sharing the CYP3A4 pathway — azole antifungals and erythromycin among them.

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