On April 21, the U.S. Food and Drug Administration announced the addition of a boxed warning to the label for propylthiouracil. The warning includes reports of severe liver injury and acute liver failure in patients using this medication. Read more at http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm209023.htm .