On Wednesday morning, the U.S. Food and Drug Administration added EpiPen, a lower-dose version called EpiPen Jr, and Mylan's own generic versions of those products to its list of drugs in shortage. She said the agency "is committed to working closely with the manufacturers to resolve the shortage as quickly as possible".
The announcement comes after hundreds of Americans reported trouble filling prescriptions for the devices.
The FDA said several factors were responsible for the injectors' "limited availability", including manufacturing issues and "pharmacy-level supply disruptions".
"We checked again today to see if we could get more and they are on back order again", says pharmacist, John Forbes.
Shares of Mylan rose $1.46 to $36.83 in early afternoon trading on the New York Stock Exchange.
Millions of people are having a hard time finding an EpiPen. The FDA website notes Mylan is receiving continual supply of the drug from Meridian and shipping to wholesalers upon receipt of the product. The problem was severe enough that the FDA put the Mylan EpiPens on its list of drugs that may experience shortages. The company also provided a phone number for patients or pharmacies having trouble locating the drug. Last September, the FDA slapped Meridian Medical Technologies with a warning letter, citing quality controls, handling of product and defective auto-injectors - among other issues - with the product.
"Our diversity and durability are what allow us to absorb evolving industry dynamics and natural market volatility, while at the same time accelerate our mission of providing access to high quality medicine", Heather Bresch, Mylan's chief executive officer, said in the statement.
Wednesday's report marked the fifth consecutive quarter Mylan has missed Wall Street's revenue expectations.
Mylan said its net income rose 31 percent to $87.1 million, or 17 cents per share, in the first quarter.