Large doses of nicotinic acid are often used for the treatment of atherosclerosis to lower blood cholesterol. In details, nicotinic acid results in a lowering of LDL cholesterol (“bad cholesterol”), in crease in HDL-cholesterol (“good cholesterol”), and a decrease in plasma triglycerides (Blakenhom et al., 1993: Holveot and Colleen, 1995; Illingrowth et al., 1994: McKenney et al., 1994). Therapy involves daily doses of 1.5-4.0 grams of niacin per day. The drug may produce troublesome side effects, such liver damage, nausea, and diarrhea. Flushing of the skin (due to dilation of arteries) occurs as a side effect when nicotinic acid therapy is started, but may disappear with continued therapy. Still, along with the statin drugs and resins that bind bile salt, niacin continues to be mainstream drug for treating or preventing cardiovascular disease.

source: nutritional biochemistry pages 603