A client is prescribed niacin for the treatment of high cholesterol. Which of the following side effects should the nurse include in the client education?

Choice A reason: Headaches are not a primary side effect of niacin, which mainly causes flushing due to prostaglandin-mediated vasodilation. Headaches may occur with other lipid-lowering drugs or unrelated conditions but are less specific to niacin’s mechanism, making this an incorrect side effect to emphasize in client education. Choice B reason: Elevated heart rate is not a common side effect of niacin, which primarily causes flushing and gastrointestinal upset. Tachycardia may occur with other cardiovascular drugs or conditions but is not typical of niacin’s prostaglandin-driven effects, making this an incorrect side effect for client education. Choice C reason: Flushing is a hallmark side effect of niacin, caused by prostaglandin release leading to cutaneous vasodilation. This transient redness and warmth, often on the face and neck, is common and expected, making it a critical side effect to include in client education to prepare for niacin therapy. Choice D reason: Black, tarry stools indicate gastrointestinal bleeding, not a side effect of niacin. Niacin may cause mild gastrointestinal upset but not bleeding. This is more associated with anticoagulants or NSAIDs, making it an incorrect side effect to include in education for niacin therapy.