1500 mgs acetaminophen in one dose

I am a long-term migraine sufferer and have been taking pain killers now for about two years. A lot of the time I will take 1500 mgs of acetaminophen in one dose. Does anyone know if this will be detrimental to my liver? I never EVER exceed the 4000mg limit in 24 hours, but I will often take 6 pills in one day, that is 1500 mgs of acetaminophen, then 1500 mgs again twelve hours later if necessary. I am very strict about the time in between each doese. So let me ask specifically:

1. Is it dangerous to take 1500 mgs of acetaminophen in one dose?
2. Is it dangerous to take 1500 mgs of acetaminophen every twelve hours?
3. How long would it take for this dosage to leave my liver completely?

[Myown]

low levels of magnesium can cause migranes (migraines)... have yours checked. The best way to absorb magnesium is thru the skin. Buy yourself Epsom salts and put about a cup in warm bath water ( after you have already showered) and just relax in the bathtub. When you get out, blot your skin dry. Do not rinse the magnesium off. It will help your headaches.

[The_Hobbit]

Thanks for the advice I appreciate it. What are your thoughts on the amount of acetaminophen I have been taking?