He was also on
Niaspan and only gets the flushing. But he had to go down to every other day on
Niaspan. So, you may have to do something like that. If you are on a very high dose of Niaspan then less common side effects can be fever, diarrhea, muscle aches, nausea, vomiting, headache and rash. But my husband is on 500mg with no problem. I don't know what they consider a high dose. The Niaspan is only really for lowering your Triglycerides not the cholesterol.