The reigning king of epinephrine auto injectors may not be king for long. Mylan Inc. (NASDAQ:MYLC) made a cool $1 billion last year from its signature EpiPen auto injector, thanks in part to legislation in 48 states designed to ensure schools have the pens on hand to protect vulnerable children from allergic reactions.However, negative publicity regarding alleged price gouging by Mylan, which raised the price of its product up to as much as $608 for a two pack (the only configuration available) and resulting pressure on the FDA may open opportunities for competition.Related: MEDICARE DOCTORS USING MORE ADVANCED MEDICAL EQUIPMENT IN THEIR OFFICESCompetition Has Been ScarceUp to now, thanks to stringent patent rules, FDA logjams and the inability of competitors to successfully design a competing device, Mylan has had nearly free rein in the marketplace.In addition, the New York State attorney general said it would investigate whether Mylan introduced “anticompetitive terms” in contracts with schools requiring districts not to purchase EpiPen-like products for 12 months in order to get a discount.Finally, Mylan has a patent on the combination drug and pen device until 2025. In order to make a generic equivalent, companies have to successfully sue Mylan in court.Players To DateNone the less, the business has significant potential and would be competitors have been making an attempt to get in on the action.One such company, Teva Pharmaceutical Industries Ltd. (NYSE:TEVAC) was granted FDA approval to make a generic EpiPen but was blocked by Mylan when that company argued Teva’s device was not identical and therefore not safe.Impax Laboratories Inc. (NASDAQ:IPXLC) subsidiary, Amedra Pharmaceuticals, maker of AdrenaClick, has a product but very limited production capabilities. As a result, the company has been unable to gain much market share.Auvi-Q, a product made by Sanofi (NYSE:SNYC) was removed from circulation in 2015 based on charges the device failed to dispense a proper dose of epinephrine when used.Coming SoonTeva plans to be back in 2017 with a reengineered version of its generic EpiPen. Impax is working to ramp up its production capabilities and even EpiPen maker Mylan says it will come out with a generic version of its signature product within weeks.Also, inhaled insulin maker MannKind Corp. (NASDAQ:MNKDD) told the Los Angeles Times it plans to develop and market an EpiPen competitor.Related: BAYER’S MONSANTO BID REACTION AND FALLOUTImpact On MylanSome analysts originally believed Mylan would be protected by its patient access program along with brand loyalty from doctors. Unfortunately for Mylan, doctors have felt pressure from patients who said they couldn’t afford the high co-pays or, in some cases, having to buy the EpiPens at retail cost.To that end, a recent poll of physicians by RBC Capital Markets found that doctors appeared ready to prescribe an alternative to the EpiPen. Brand loyalty, it turns out, may have its limits.