I am 63 yr old female. I started taking 1000mg. niacin SR 5 days ago. Yesterday after dinner I experience some slight jaw discomfort and just felt odd. I took my pulse and it was racing at 160bpm. This episode lasted about 5 min. and then I was fine. I had no shortness of breath or pain anywhere else. Would the niacin cause this? I was also taking 500mg. CLA. Could that be the cause. I have no known heart problems.