Seven deaths attributed to Epipen malfunctions have been reported so far this year in the United States, Food and Drug Administration records show.
As of mid-September, there had been a total of 228 reports of EpiPen or EpiPen Jr. failures. Along with the deaths, 35 people were hospitalized, according to FDA documents made available under a Freedom of Information request by Bloomberg News.
EpiPens inject the hormone epinephrine (also known as adrenaline) in order to treat potentially fatal allergic reactions. The devices are made by Pfizer Inc.'s Meridian Medical Technologies and sold by Mylan MV.
Accounts of EpiPen malfunctions have been rising in recent years, Bloomberg reported.
The FDA database shows that in 2012, there were four reports of EpiPen and EpiPen Jr. failures to the agency, rising to 12 in 2013. In 2014, there were 67 reports, a more than 400 percent increase from the previous year.
"We are not aware of defective EpiPens currently on the market and recommend that consumers use their prescribed epinephrine auto injector," the FDA said in an emailed statement Tuesday, Bloomberg reported.
"We have seen circumstances in which adverse events reports increase once a safety issue is publicized, like a recall. We continue to monitor and investigate the adverse event reports we receive," the agency said.
The FDA documents don't explain how the EpiPens failed. However, a warning letter sent in September said FDA investigators who inspected Meridian's Missouri plant earlier this year found that epinephrine had leaked out of the devices in some cases and that the injectors didn't work properly in other cases, Bloomberg reported.
In a statement on Tuesday, Mylan said it was "confident in the safety" of the EpiPen. In a second statement issued on Thursday, the company said all adverse event reports "have been investigated by Pfizer and Mylan and reported to FDA. One needs to keep in mind that an anaphylaxis event can be deadly and, sadly, even an appropriately administered dose of epinephrine from a fully functional device may not prevent a patient from dying. We have not identified any causal connection between any reported patient deaths and Mylan's epinephrine auto injector products."
In a statement emailed to Bloomberg on Thursday, Pfizer said it is "confident in the quality, safety and efficacy of EpiPens manufactured by" its Meridian subsidiary. However, the company noted that "in the case of EpiPen, adverse events can also be due to epinephrine itself, for a variety of reasons as reflected in the product label."