In 1971, the Food and Drug Administration approved the first drug that could reverse a heroin or opioid overdose. More than 40 years later, makers of this drug, called naloxone, are cashing in on the nation’s opioid painkiller and heroin epidemic and price-gouging consumers.

According to a group of researchers, the cost of one package of Evzio — a branded version of the lifesaving injection — has quickly risen from $690, when it hit the market in 2014, to $4,500. Evzio is the first auto-injector formulation, which means anybody, not just first responders or doctors, can easily use it to save their own lives or the lives of others.

That’s not all. The researchers, who studied the rising price of naloxone for a paper in the New England Journal of Medicine, found price hikes in other formulations of the drug: An injectable by Hospira has increased in price from $62.29 in 2012 to $142.49 today, while a nasal spray version of naloxone by Amphastar now costs $39.60 — a 95 percent surge since 2014.

Drug overdoses kill more people than car crashes and gun violence in America, and these overdose antidotes have never been more important. But they’re also quickly becoming more unreachable for the people whose deaths they could avert.

Drugmakers do this because they can

Kaleo, the drug company behind Evzio, says the price increases are justified because of its easy-to-use and life-saving delivery system, as Shefali Luthra at Kaiser Health News reports. But, Luthra adds, the jump in price is “way out of step with production costs.”

In reality, Kaleo — like the EpiPen makers who hiked the price of their injectable by 400 percent since 2007 — increased its cost because it can.

The US drug pricing scheme is set up in a way that makes it relatively easy for companies to charge what they want — unlike countries with single-payer health systems, where governments exert much more influence over the entire health care process. In England, for example, the government has an agency that negotiates directly with pharmaceutical companies. The government sets a maximum price that it will pay for a drug, and if companies don't agree, they simply lose out on the entire market. This puts drugmakers at a disadvantage, driving down the price of drugs.

The US doesn’t do that. Instead, America has long taken a free market approach to pharmaceuticals. Drug companies haggle separately over drug prices with a variety of private insurers across the country. Meanwhile, Medicare, the government health program for those over 65, which is also the nation's largest buyer of drugs, is actually barred from negotiating drug prices.

That gives pharma more leverage, and it leads to the kind of price surges we’ve seen with EpiPen and now with these opioid antidotes. “The EpiPen and Evzio situations have a lot of parallels,” said NEJM study author and Yale professor Joseph Ross, “persistently raising prices for a product that makes use of a novel delivery system to provide a decades old, off-patent drug.”

Unlike EpiPen, though, the naloxone price increases haven’t garnered much attention or outrage, maybe because of the stigma that comes with opioid addiction.

In the face of an out-of-control opioid epidemic, the outrage better come soon.