It wouldn't hurt to check our livers a couple of times per year, but generally speaking, liver damage is said to be more prevalent in high doses 2000mg to 3000mg PER DAY. Even then I understand that it happens in 2 to 3% of the users.
http://www.drugs.com/sfx/niacin-side-effects.html for instance. Even so, the majority of high dosage users report few problems.
Niacin is used for POIS in much lower doses and with a frequency way below the danger threshold.
There is always potential for allergic reactions to any drug, which should be watched out for or any preconditions that could be adversely affected by niacin. Check all the internet references and then check with your doctor if you have any doubts.