Pharmacology
Summary
Fibrates (e.g., gemfibrozil, fenofibrate) primarily manage hypertriglyceridemia by activating the PPAR-alpha receptor. This increases lipoprotein lipase activity, reducing VLDL levels by 35-50% and serum triglycerides. They mildly increase HDL and variably affect LDL. Notable risks include myopathy and a heightened risk of cholesterol gallstones, necessitating caution in those with biliary susceptibilities.
Niacin (vitamin B3) reduces VLDL triglycerides and increases HDL, by inhibiting hepatic VLDL secretion. Its use is sometimes limited by side effects like cutaneous flushing and may cause hepatotoxicity, requiring regular monitoring of LFTs. Fish oil, rich in omega-3 fatty acids, is a comparable alternative in triglyceride reduction and offers additional cardiovascular advantages.
Lesson Outline
Don't stop here!
Get access to 133 more Pharmacology lessons & 13 more medical school learning courses with one subscription!
FAQs
Fibrates and niacin are both lipid-lowering agents that help manage cholesterol and triglyceride levels. Fibrates, such as gemfibrozil and fenofibrate, mainly target serum triglycerides by reducing the production of VLDL, a precursor to LDL cholesterol. This leads to a mild reduction in LDL cholesterol and a mild rise in HDL cholesterol. Conversely, niacin not only lowers LDL cholesterol and boosts HDL cholesterol but also diminishes triglycerides by diminishing VLDL production.
Flushing, a common side effect of niacin, is characterized by a sensation of warmth and reddening of the skin and is often the reason for poor patient adherence. One strategy to manage this side effect is the concomitant use of NSAIDs, such as aspirin, taken about 30 minutes before the niacin dose, to mitigate the prostaglandin release behind niacin-induced flushing
Fibrates, such as gemfibrozil and fenofibrate, may cause myopathy, a notable adverse effect. Additionally, these drugs can increase the risk of developing cholesterol gallstones, making them potentially risky for patients with biliary tract disease or those predisposed to such conditions.
Fish oil, rich in omega-3 fatty acids, is a compelling alternative to drugs like fibrates and niacin. Its efficacy in reducing serum triglycerides (by decreasing VLDL and apoB production) is comparable to these agents. Moreover, fish oil has been associated with improvements in several cardiovascular risk factors.
Niacin, also or vitamin B3, is employed in lipid management due to its ability to reduce VLDL triglycerides and elevate HDL levels. It operates by inhibiting VLDL secretion in the liver and diminishing triglyceride release from adipose tissues.
MCAT® is a registered trademark of the Association of American Medical Colleges. The United States Medical Licensing Examination (USMLE®) is a joint program of the Federation of State Medical Boards (FSMB®) and National Board of Medical Examiners (NBME®). NAPLEX® is a registered trademark of the National Association of Boards of Pharmacy. PANCE© is a registered trademark of the National Commission on Certification of Physician Assistants. NCLEX® is a registered trademark and service mark of the National Council of State Boards of Nursing, Inc. None of the trademark holders are endorsed by nor affiliated with Sketchy or this website.
