"FDA Drug Safety Communication: FDA Recommends Against Prolonged Use of Magnesium Sulfate to Stop Pre-term Labor Due to Bone Changes in Exposed Babies" 
FDA May 30
http://www.fda.gov/Drugs/DrugSafety/ucm353333.htm

"FDA Drug Safety Communication: FDA approves new label changes and dosing for zolpidem products and a recommendation to avoid driving the day after using Ambien CR" 
FDA May 14
http://www.fda.gov/Drugs/DrugSafety/ucm352085.htm

CDC Health Advisory: "Human Infections with Novel Influenza A (H7N9) Viruses"
CDC April 5
http://www.bt.cdc.gov/HAN/han00344.asp