How long does it take for liver failure because of too much tylenol (acetaminophen)?

Tylenol (acetaminophen) nomogram : It depends on Tylenol (acetaminophen) dose taken, if sufficient it make about 4-5 hours for a liver failure to develop. Tylenol (acetaminophen) level can be checked and treatment should be determined according to Tylenol (acetaminophen) nomogram.

See your doctor: Appropriate dosing should not lead to liver failure. But if you've been taking large doses accidentally or intentionally even for a short period , you should see your physician immediately particularly if you have stomach upset or any other gastrointestinal symptoms.