last night I had a NE (actually it was not that nocturnal, i woke up immediately after, looked at the time, it was 7.00am) .
a couple of hour later (when i finally found the strenght to stand up) I took 100mg niacin on an empty stomach.
in 20 minutes got a strong flush that lasted for 40 minutes more or less.
afterwards I started feeling better and with 80% less of symptoms for the whole day.
at the moment i took the pill, POIS didn't reach the peak of symptoms, because I was not active yet (didn't have breakfast, didn't go to bathroom, still laying on bed)
but something different happened to me a week ago.
I had the need to have an O and I hadn't got niacin with me.
afterwards I had a walk and could take 100mg of niacin an hour later, when the symptoms had already reached their peak (i fasted for 4 hours more or less).
immediately afterwards my symptoms disappeared, but in 20-30min i got the flush and the symptoms came back and lasted for the whole day long.
so maybe to have more flexibility with niacin, it would be enough have an O at night, then take niacin and going to sleep after getting the flush. I'll test it next week and inform you