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Fibrates, niacin

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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.

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FAQs

What are fibrates and niacin, and how do they function as lipid-lowering agents?

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.

How can the flushing side effect of niacin be managed?

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

What adverse effects are associated with fibrates?

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.

How does fish oil compare with other triglyceride-lowering agents?

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.

What is niacin's role in lipid management?

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.