An interesting read from Pro Publica
For prescription drugs, the FDA can require so-called black box warnings when drugs pose a potentially "serious or life-threatening" risk. The agency requires all prescription drugs containing acetaminophen to carry a black box warning that an overdose can result in liver transplant or death. For over-the-counter Tylenol and its generic equivalents, the FDA requires no warning that overdose can be fatal.
http://www.propublica.org/getinvolved/item/should-fda-require-all-acetaminophen-drugs-carry-black-box-warnings
