Niacin weirdness

I took 500 mg of niacin last night. Had actually forgotten to take any since Sunday at which time I had no weird reaction other than the flush which is kinda cool and relaxing.

Last night not so much. About a half hour into it I felt cold sweat and had the most intense stomach cramps I've ever had in my life (seriously, no exaggeration) and felt like I had to go to the bathroom. Went in there and literally sat on the toilet with horrifying abdominal cramps, finally went to the bathroom, but actually passed out briefly from the intensity of it all. I basically had the cramps AND was at the apex of the niacin at the same time.

Haven't a clue where the cramps came from. I'll probably get the flush free niacin this weekend but wonder if anyone has had a reaction like this.

Interestingly, I felt throughout that I was rounding a corner somehow with my health and awakened this morning with a 98.3 temp and alert.

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