The parents of a University of Oklahoma sophomore who died from acetaminophen overdose want others to know taking too much Tylenol isn't safe. Madalyn Byrne , 19, died Monday from liver damage and cardiac arrest from taking too much acetaminophen, the active ingredient in Tylenol and many other commonly used medicines. She had taken, her parents and physicians estimate, nine extra-strength Tylenol pills a day ove...