Which class of lipid-lowering agents may cause flushing as a side effect?

Flushing is a well-known side effect specifically associated with niacin, a B-vitamin that plays a role in lipid metabolism. When niacin is taken, it causes the release of prostaglandins, leading to vasodilation, which manifests as flushing, particularly in the face, neck, and upper body. This flushing can be uncomfortable for patients but is typically dose-dependent and may decrease over time with continued use.

In contrast, statins, fibrates, and PCSK9 inhibitors do not commonly lead to flushing. Statins primarily work by inhibiting HMG-CoA reductase, thus lowering cholesterol production in the liver, and their side effects are more centered around muscle-related issues and liver enzyme elevations. Fibrates primarily reduce triglyceride levels and improve HDL cholesterol but are known for side effects like gastrointestinal issues and muscle pain rather than flushing. PCSK9 inhibitors are monoclonal antibodies that help the liver absorb more LDL cholesterol and have a different side effect profile that typically does not include flushing.

Therefore, the association of flushing with niacin is a key characteristic that distinguishes it from the other classes of lipid-lowering agents.