I just flew for the first time in years last week. So we perused the TSA website and got all the info we needed there. http://www.tsa.gov/travelers/airtravel/assistant/editoria...
"Medically necessary liquids and gels, including medications, baby formula and food, breast milk, and juice are exempt from the 3-1-1 rules, and are allowed in reasonable quantities exceeding 3.4 ounces (100ml). They are not required to be in a zip-top bag. Officers may ask travelers to open these items to conduct additional screening and passengers should declare them for inspection at the checkpoint.
Please be advised that passengers going on long trips should only carry on the medically necessary liquids and gels needed for their infant/toddler’s immediate comfort during the flight. Please pack larger amounts of liquids for the remainder of the trip in a checked bag.
Lastly, avoid any additional hassles by making sure nothing you plan to pack is on TSA’s list of prohibited items. Learn more on the Prohibited Items page."
My grandmother has to travel with an epi pen. She carries a dr. note with her just in case, although she was never asked about it during her travels. SHe just wanted in to avoid any hassles while out of state.