Pharmacology · patient case question
What is the mechanism of action of simvastatin?
Patient case: Chest Pain During the Appointment
Patient: 64-year-old female
Chief Complaint: “My mouth is hurting on the upper right.”
Background: Hyperlipidemia and hypertension, both reportedly well controlled. Non-smoker. No prior cardiac events.
Medications: Simvastatin 40 mg daily · Carvedilol 12.5 mg twice daily · Aspirin 81 mg daily
Vital Signs: On seating: BP 138/84 mmHg · HR 68 bpm · RR 16 · T 98.4°F
Findings: During the examination she develops crushing substernal chest pain radiating into the left arm, with diaphoresis. Emergency medical services are activated, oxygen is delivered, and a sublingual nitroglycerin tablet is administered. Her panoramic radiograph, taken earlier, incidentally shows diffusely narrowed pulp chambers and canals in multiple posterior teeth.
Show answer and explanation
Correct answer: B. Inhibits HMG-CoA reductase
- A. Incorrect. That is ezetimibe, which blocks the NPC1L1 sterol transporter in the intestinal brush border.
- B. Correct. Statins competitively inhibit HMG-CoA reductase, the rate-limiting enzyme of hepatic cholesterol synthesis. Falling intracellular cholesterol upregulates hepatic LDL receptors, which clears LDL from the circulation.
- C. Incorrect. Lipoprotein lipase activation is the mechanism of the fibrates such as gemfibrozil and fenofibrate, which are used primarily to lower triglycerides.
- D. Incorrect. That describes the bile acid sequestrants — cholestyramine, colesevelam — which interrupt enterohepatic recirculation of bile acids.