Almost 4 million prescriptions were dispensed last year for EpiPens. (Drew Angerer/Getty Images)

Paulette saw it happen at the playground from several feet away, the panic-inducing moment in 2014 when her 3-year-old son Charlie, who has a life-threatening allergy to milk, grabbed a playmate's sippy cup and took a gulp.

Thankfully, Paulette had the anaphylaxis-stopping EpiPen and was able to quickly use the auto-injector on her son. But when she pulled the needle from his thigh, it was sticking out of the device at an angle instead of being under an orange cover, leaving her unsure whether the lifesaving medicine had been administered. Not wanting to take a chance, Paulette (who asked that her last name not be used to protect her son's identity) called 911, and Charlie was rushed to a hospital where he remained for several hours until doctors were sure he was all right.

"He was okay, but it was nerve-racking to say the least, not knowing if the EpiPen had worked or not," she said.

Not everyone has been as lucky.

EpiPens, which contain the hormone epinephrine (also known as adrenaline), are used to stave off allergic reactions that can be fatal. Failure of EpiPens to deploy correctly have been cited in seven deaths this year through mid-September, according to patient and physician reports made to the Food and Drug Administration and obtained by Bloomberg News. The FDA received 228 reports of EpiPen or EpiPen Jr. failures during that period, according to documents made available as a result of a Freedom of Information Act request. In addition to the deaths, 35 people were hospitalized, according to the reports.

The medical device has been the subject of attention for a different reason before this. EpiPen is sold by Mylan, which came under fire last year for significantly raising the price of the fast-acting allergy shot, from about $50 for a single pen to more than $600 for a two-pack. Congress held hearings, government agencies began inquiries, and rival Sanofi sued, claiming that Mylan had sought "to preserve the monopoly position of their $1 billion crown jewel" by engaging in conduct that was anti-competitive. Mylan has denied any wrongdoing.

Failures of the EpiPen and EpiPen Jr., meanwhile, resulted in a recall of some units in March by Meridian Medical Technologies. Mylan, which sells the drug-device combo using Meridian's "pens," called the defect "extremely rare." 

Reports submitted by users to the FDA, however, show broadening accounts of malfunctions dating as far back as 2014.

In 2012, there were four reports to the FDA of EpiPen and EpiPen Jr. failures, followed by 12 in 2013, according to an agency database. (The EpiPen Jr. contains a dose of epinephrine intended for small children.) In 2014, there were 67, according to the reports obtained by Bloomberg News.

It's important to note that these reports — called adverse event complaints — don't confirm that a product caused the incident. At the same time, such reports typically don't depict the full extent of a problem, given that most people don't know they can submit them.

Pfizer, the parent company of Meridian, has previously said consumer complaints aren't unusual when a product "is frequently administered by non-medically trained individuals." In an emailed statement last week, the company said it's "confident in the quality, safety and efficacy of EpiPens manufactured by" Meridian. Pfizer noted, however, 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."

For its part, Mylan said it was "confident in the safety" of the EpiPen product "being produced at Pfizer's manufacturing site. Testing and analysis across lots impacted by the recall have not identified any units with a defect."

Although the reports provided by the FDA don't explain how the EpiPens failed, FDA investigators who inspected Meridian's Missouri plant this year said in a warning letter sent in September that epinephrine had in some cases leaked out of the pens. In other cases, the injectors didn't work properly, the regulator said.

"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. "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 auto-injecting pen was developed by Survival Technology, which ended up becoming Meridian. The device was originally used to administer the drug lidocaine for people with irregular heartbeats. Around the same time, the U.S. military approached Survival about using the device to administer treatments for chemical warfare, and NASA astronauts reportedly used a similar approach for nutrition delivery.

Mylan bought the right to sell and market the EpiPen in 2007 from Merck KGaA. Meridian has made the auto-injector for Mylan the entire time and has primary manufacturing responsibilities, Mylan spokeswoman Julie Knell said in an email.

The EpiPen's design has changed in recent years, including tweaks to the orange cap where the needle in Paulette's device should have been after she injected her son. Mylan said the advances are crucial to the pen's safety and functionality, but the changes also protect it from competition by generic device makers until 2025.

In its warning letter, the FDA noted that Meridian staff had said the company initiated a recall of some EpiPens only after government prodding. The agency said inspectors found the device maker had "failed to thoroughly investigate multiple serious component and product failures" for EpiPen products, "including failures associated with patient deaths and severe illness." The FDA at the time didn't specify how many had been hurt or had died.

But even before the recall, the FDA received 105 complaints of EpiPen failures in 2016.

"This is a lifesaving product," Diana Zuckerman, president of the National Center for Health Research, said. "If it fails 105 times, that's significant."

Almost 4 million prescriptions were dispensed last year for EpiPens, according to data compiled by Bloomberg News.

— Bloomberg News