Back-to-school season can be an expensive time for families, and parents of children with severe allergies now have another rising cost on their hands.

According to multiple reports, the cost of an EpiPen, a potentially life-saving medical device used in the event of an allergic reaction, has risen exorbitantly in just a few short years, putting some adults in a financial bind to protect their kids.

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NBC News reported this week that the pharmaceutical company, Mylan has been accused of increasing EpiPen costs by more than 400 percent over the past eight years. EpiPens are portable devices in the shape of a pen that are used to inject epinephrine into the body of someone having an allergic reaction. In 2008, an EpiPen cost roughly $100, but the price has risen to $500 for an EpiPen today. And due to the fact that Mylan's major competitor had a recall last year, Mylan has significant control over the market.

Dr. Douglas McMahon, an allergy specialist trying to develop his own version of the EpiPen for a much more affordable rate, told NBC News that some of his own patients have called to say they cannot pay for the device.

"When epinephrine only costs a few cents, but they're going up to $500, personally I don't think that's ethically responsible," Dr. McMahon said.

Mylan said in a statement that costs have shifted to "better reflect important product features and the value the product provides," and that the company has made "a significant investment to support the device over the past years." But Tracy Bush, a food allergy consultant, who has been buying EpiPens for her son for the past decade and has experienced the rising costs firsthand, does not feel the product has significantly improved overtime.

Many others, including Sen. Bernie Sanders (I-Vt.), have condemned Mylan for the price jump.

More than 3.6 million people in the U.S. have EpiPen prescriptions, Slate reported, and the effectiveness of EpiPens can decrease once they expire, which is typically over the course of a year. However, some people keep their EpiPen devices beyond the expiration date, due to rising EpiPen costs. Last month, a 20-year-old named Morgan from the University of Denver told The Denver Post that it makes the most financial sense to use his current EpiPens as backup devices during his semester abroad even though they will expire while he is away.

“Fudging it a little is a step down, not the best outcome,” Morgan said. “It’s not the most comfortable option, but it’s the one we have because of the cost.”