CLS Non-Statin Lipid-Lowering Pharmacotherapy 2 ā Questions and Answers
Question 1: What is the primary mechanism of action of fibrates?
- Inhibit HMG-CoA reductase to reduce hepatic cholesterol synthesis
- Block the NPC1L1 cholesterol transporter in the small intestine
- Activate peroxisome proliferator-activated receptor alpha (PPARĪ±) (Correct answer)
- Inhibit PCSK9 to upregulate LDL receptors
Correct answer: Activate peroxisome proliferator-activated receptor alpha (PPARĪ±)
Fibrates activate PPARĪ±, a nuclear receptor that increases lipoprotein lipase expression, reduces apoC-III production, and increases apoA-I synthesis, resulting in reduced triglycerides and increased HDL-C.
Question 2: Which fibrateāstatin combination carries the greatest risk of severe myopathy and rhabdomyolysis?
- Fenofibrate + rosuvastatin
- Gemfibrozil + any statin (Correct answer)
- Fenofibrate + ezetimibe
- Fenofibrate + atorvastatin
Correct answer: Gemfibrozil + any statin
Gemfibrozil inhibits the glucuronidation pathway responsible for statin metabolism, raising statin plasma concentrations significantly and increasing the risk of myopathy and rhabdomyolysis; fenofibrate does not share this interaction.
Question 3: For which lipid abnormality are fibrates considered first-line pharmacotherapy?
- Elevated LDL-C (>190 mg/dL)
- Severe hypertriglyceridemia (ā„500 mg/dL) (Correct answer)
- Elevated Lp(a)
- Low HDL-C as isolated finding
Correct answer: Severe hypertriglyceridemia (ā„500 mg/dL)
Fibrates reduce triglycerides by 20ā50% and are indicated as first-line pharmacotherapy for severe hypertriglyceridemia (ā„500 mg/dL) to reduce pancreatitis risk.
Question 4: What is the most notable lipid effect of niacin (nicotinic acid) compared to other lipid-lowering agents?
- Greatest LDL-C reduction
- Greatest triglyceride reduction
- Greatest HDL-C increase (Correct answer)
- Greatest Lp(a) reduction
Correct answer: Greatest HDL-C increase
Niacin raises HDL-C by 15ā35%, which is the largest HDL-C increase achievable with any single pharmacologic agent currently available.
Question 5: What did the AIM-HIGH and HPS2-THRIVE trials of extended-release niacin in statin-treated patients demonstrate?
- Significant reduction in major adverse cardiovascular events
- No additional cardiovascular benefit and increased adverse events (Correct answer)
- Significant reduction in all-cause mortality
- Improved outcomes specifically in patients with very low HDL-C
Correct answer: No additional cardiovascular benefit and increased adverse events
Both AIM-HIGH and HPS2-THRIVE found no cardiovascular benefit from adding niacin to statin therapy and documented increased adverse events including hepatotoxicity and serious infections, substantially reducing niacin's clinical use.
Question 6: What is the most common adverse effect of niacin, and what can reduce its severity?
- Hepatotoxicity; reduced by taking niacin with food
- Hyperuricemia; reduced by adequate hydration
- Cutaneous flushing; reduced by taking aspirin 30 minutes before the dose (Correct answer)
- Myopathy; reduced by dividing the daily dose
Correct answer: Cutaneous flushing; reduced by taking aspirin 30 minutes before the dose
Cutaneous flushing (prostaglandin D2-mediated vasodilation) occurs in up to 75% of patients taking niacin and can be significantly attenuated by taking 325 mg aspirin 30 minutes before the niacin dose.
Question 7: Fenofibrate requires dose adjustment or avoidance in patients with which condition?
- Hypertension treated with ACE inhibitors
- Type 2 diabetes mellitus on insulin
- Chronic kidney disease or renal impairment (Correct answer)
- Hypothyroidism on levothyroxine
Correct answer: Chronic kidney disease or renal impairment
Fenofibrate is primarily renally eliminated and can worsen renal function; dose reduction is required for eGFR <60 mL/min/1.73mĀ², and it should be avoided in severe renal impairment (eGFR <30 mL/min/1.73mĀ²).
CLS Non-Statin Lipid-Lowering Pharmacotherapy 2
What is the primary mechanism of action of fibrates?