LESH-
YES! I take Slo-Niacin 1000 (2-500Mg. pink oblong tablets made by Upsher-Smith) and have been for the last 3 years. Prior I was Niaspan 2000Mg. 2 years but like you My liver numbers were tickling the high end My Hdl was 48 so I cut back to 1000Mg. and found the Slo-niacin at $18 a 100 was alot cheaper then the abbott price. So I did the switch and Hdl hung and stayed at 45 mg/dl. So here I'am 2 pills a gulp of water and into bed and out! Don't know what a flush feels like if I have them I'm not there for them.
The only way to find out is to cut down to 1000 for a month or two and get your numbers checked and see what you get.
That still leaves you with the 1500 option.
Hope this helps!