I have written here previously about trying large doses of niacin to help with my chronic high blood pressure. I had gone from 100 mgs a day to 500 mgs of niacin a day recently. Recommendations for daily niacin intake range from 12 to 35 mgs, so I was moving way beyond that (a friend takes it in the grams-per-day dosage range and had reported positive results, prompting me to try it as well).
In the first few days of my experiment at 500 mgs, I had episodes each morning where my vision completely blurred and I literally could not see well enough to type or read my computer screen at work. Those prompted me to make an eye doctor appointment, fearful that my cataracts had reached the point where surgery was required. The eye doctor told me it was too soon for surgery.
I didn’t mention the niacin to her because I had already stopped taking it. Those morning bouts of blindness seem to have stopped since I did.
I’m going back to lower doses of niacin now to see if it will help on the blood pressure front. In the three months I was taking it, it hadn’t. My daily readings were still 167/109, even after taking my blood pressure medications. That is too high but niacin doesn’t seem to be my answer.