Learning Objective:

By the end of this section, learners should be able to explain the mechanism by which niacin lowers plasma lipids, recognize its effects on triglycerides, VLDL, and LDL cholesterol, and identify its major adverse effects and management strategies.

Mechanism of Action

• Niacin inhibits lipolysis in adipose tissue by decreasing cAMP in adipocytes.
• Result: Fewer free fatty acids are released into the circulation.
• Hepatic effect: Reduced free fatty acids → decreased hepatic triglyceride synthesis → decreased VLDL production → lower LDL cholesterol.
• Also increases HDL cholesterol by decreasing HDL clearance.

Clinical Effects

• ↓ LDL cholesterol
• ↓ triglycerides / VLDL
• ↑ HDL cholesterol
• Useful for patients with mixed dyslipidemia or low HDL.

Adverse Effects

• Flushing, pruritus, and burning sensations – mediated by prostaglandin D2- can be reduced with aspirin premedication.
• Hepatotoxicity – monitor liver function tests.
• Metabolic: Can cause hyperglycemia; caution in diabetic patients.

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Clinical Considerations

• Niacin is often used as adjunct therapy when statins alone do not achieve target lipid levels.
• Requires monitoring for liver toxicity and metabolic effects.

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