I've been on at most 1800mg of tylenol (acetaminophen) a day for 1 yr a half for a herniated disk and severe tmj, should i be concerned about liver issues i'm 22?

1800 mg Tylenol/day: is well within the normal amount of it and at your young age I am sure its okay, but if you are concerned, then seeing your PCP and having some LFT's ( Liver Function tests) would satisfy the curiosity. Good Luck and Happy Holidays.

Probably not: Not a high dose. You may want to have your MD check your liver function tests to make sure.

4,000 mg/max/day: 1800 mg of Tylenol (acetaminophen) in a day is a safe dose. Ask your doctor about about rehabilitation, exercise and alternative treatments for a herniated disc and TMJ.