WASHINGTON — (CNN) On a hot and sticky summer day in Manhattan, Nicole Levin was leaving a dentist appointment when it happened.

The 41-year-old New Yorker exited a subway train, walked up a flight of concrete stairs to the bustling city street, and suddenly felt her tongue and throat swell.

She started to sweat. She felt nauseous, short of breath and couldn’t swallow.

If Levin let any more time pass, she knew she wouldn’t be able to breathe.

She frantically opened her purse, wrapped her fingers around an EpiPen, and jammed it into her thigh beneath her workout pants.

Immediately, she felt her throat open. She took in a deep breath of air — a sigh of relief.

“That was really scary, because usually I can do it at home or something and this time I didn’t know what hit me. I just pulled it out and had to do it right in the subway,” said Levin, who has a combination of environmental, food and medication allergies, often leading to cross-reactivity.

Just moments earlier, Levin received a tooth implant at her dentist appointment.

She told the clinicians that she was allergic to amoxicillin, an antibiotic that can treat infections, she said.

However, they prescribed a medication that was still in the same penicillin family, which she said caused the reaction.

“That’s why I need EpiPens, because I don’t know what to avoid,” Levin said, referring to the portable auto-injector devices used to treat allergic reactions.

“Because of my history, I’m really supposed to have four with me at all times, and when I travel, I’m supposed to have like six or eight,” she said.

“Usually, one is not enough because the reaction is immediately severe, so there are times where I have to use up to three until I can get help.”

And what does that life-saving medication cost her?

“Right now, it’s $200 each or even $300.” For some, it costs even more.

The EpiPen is an auto-injector that delivers epinephrine, more commonly known as adrenaline, a hormone that can help to relax muscles.

It can open the airways, and reduce swelling during a severe allergic reaction.

Indeed, the price of an EpiPen standard two-pack gradually grew to about $600. The same two-pack cost only about $100 in 2009.

Meanwhile, epinephrine, which can be purchased alone, costs just a few dollars.

The EpiPen, manufactured by the pharmaceutical company Mylan, offers a portable way to administer doses.

“Some patients and physicians are resorting to buying epinephrine ampoules and filling their own syringes,” said Dr. Thomas Casale, a professor of medicine at the University of South Florida and executive vice president of the American Academy of Allergy, Asthma, and Immunology (AAAAI).

Many adults and families of children with severe allergies are facing sticker shock when they pay for their EpiPens, especially amid back-to-school season.

Theresa Ray, a 30-year-old mother in Cincinnati, was surprised to find that purchasing two EpiPen two-packs for her 6-year-old son would have cost her family about $1,300, she said.

Her son was diagnosed with food allergies five years ago.

“When we first bought them (about five years ago), it was around $100 or $150 for a twinpack, and at that time I remember thinking, ‘Wow, that’s kind of expensive.’ Then, the next year, I found out they expired and we have to get them every year. They were more expensive, but by that time, only a couple hundred dollars,” Ray said.

“Last year, we spent around $650 for a twinpack and this year, same thing,” she said. “It was funny, I told my husband, ‘I wonder why no one’s talking about this. It’s really weird no one’s talking about EpiPens.’ … And then, I saw a news article on Facebook about it.”

Net spending on prescription drugs by consumers in the United States has increased about 20% between 2013 and 2015, according to a new paper published in the Journal of the American Medical Association on Tuesday.

Prescription drugs also cost about twice as much in the United States compared to other advanced nations.

In other words, EpiPens are not the only prescription drugs with steep price hikes.

For instance, when Turing Pharmaceuticals increased the cost of Daraprim, a drug used by some cancer and AIDS patients, from $13.50 to $750 last year, it sparked outrage.

The pharmaceutical company’s former CEO was Martin Shkreli, known as “pharma bro.” Albuterol, an asthma medicine, has also increased in price in recent years.

A House of Representatives report found in 2014 that 10 generic drugs experienced price increases just a year prior, ranging from a 420% hike to more than 8,000%.

Now, the new study suggests that a combination of market exclusivity provisions granted to drug manufacturers, and coverage requirements imposed on government-funded drug benefits, are both driving the high costs of prescription drugs nationwide.

“I continue to be impressed by the complexity of the issue. It is not as easy as saying, ‘Let’s let Medicare negotiate for Part D drugs,’ or any simple fix,” said Dr. Aaron Kesselheim, an associate professor at Harvard Medical School and associate physician at Brigham and Women’s Hospital, who was lead author of the paper.

“There are problems at every level — including inefficient government policies, Food and Drug Administration regulatory rules, physician prescribing practices — that contribute to manufacturers’ abilities to charge high prices, leading to high drug spending, and unfortunately suboptimal public health outcomes,” he said. “It is going to be very important to consider the impact of any proposed changes on the many different contributors to the issue.”

Kesselheim and his colleagues reviewed and analyzed previous papers published in medical and health policy journals from January 2005 to July 2016, taking a close look at how each explained the cause of rising drug prices and how to possibly reduce costs.

Based on their analysis, the researchers found that the primary reason for increasing drug spending is the high price of branded products.

While only about 10% of all prescription drugs in the country are brand-name drugs, such as the EpiPen, they account for a whopping 72% of drugs being sold, the researchers discovered.

For patients who may not be able to afford EpiPens, there are limited alternatives.

Another epinephrine auto-injector, Auvi-Q, left the market last year after a recall.

On the market, there is Adrenaclick, a generic medication that offers an emergency injection of epinephrine, according to Consumer Reports.

It uses a different technology, but administers the same medicine for around $200.

Are there any other options? “The ER,” Levin said. “You know, if you can call an ambulance. But when my airways are blocked, I can’t talk. So, there’s no other option.”

The AAAAI has expressed concern about the rising cost of epinephrine auto-injectors and advocates for more affordable medications for all diseases.

“Unfortunately, the shelf life of epinephrine is not very long and the need to refill prescriptions on an annual basis can result in a financial burden for patients,” Casale said.

“As a result, some patients are carrying epinephrine auto injectors that are expired because they cannot afford to refill a prescription,” he added. “Others, when they find out the price of an epinephrine auto injector, failed to fill their prescription.”

Minnesota Sen. Amy Klobuchar has called on the Senate Judiciary Committee to hold a hearing to investigate the rising price of EpiPens.

“Patients all over the United States rely on these products, including my own daughter. Not only should the Judiciary Committee hold a hearing, the Federal Trade Commission should investigate these price increases immediately,” Klobuchar, a Democrat, said in a written statement that was released on Saturday.

“The Commission should also report to Congress on why these outrageous price increases have become common, and propose solutions that will better protect consumers within 90 days.”

Iowa Sen. Chuck Grassley, a Republican, announced Monday that he had contacted the company Mylan seeking answers as to why there has been a steep price increase in the product in recent years.

As the cost of EpiPens has been gradually rising, so has the number of patients in high-deductible health plans — alas, the impact of the cost on patients seems to be a problem that’s two-fold, said Dr. Purvi Parikh, an allergist and immunologist at NYU Langone Medical Center and an allergist with the Allergy & Asthma Network.

“While the price is increasing, the other issue now is that the health insurance plans have now put more and more responsibility on the patient,” said Parikh, who also serves as Levin’s doctor.

“It’s definitely unfortunate because it’s a necessary lifesaving medication. It’s not really a luxury,” Parikh said. “It’s a single-use medication and you need it available everywhere you go, so often our patients will have multiple sets of EpiPens at home, school, work. So it’s a huge cost on the patient.

“Not only have I seen it save lives, but I’ve seen the opposite happen, of when an EpiPen wasn’t available and both children and adults passed away.”

A spokeswoman for Mylan emailed a written statement from the company to CNN. In the statement, company officials indicated that they know more is needed to help patients with high-deductible insurance plans.

“With changes in the healthcare insurance landscape, an increasing number of people and families are enrolled in high-deductible health plans, and deductible amounts continue to rise. This shift has presented new challenges for consumers, and they are bearing more of the cost. This change to the industry is not an easy challenge to address, but we recognize the need and are committed to working with customers and payors to find solutions to meet the needs of the patients and families we serve,” according to the company’s statement.

Levin, the patient in New York, said that her EpiPen costs are partly covered by insurance, but she has to first pay a separate deductible under the category of injectables before she can purchase her EpiPens at the discounted insurance price.

“Five years ago, the deductible was only $100, but as the price increased, so did the deductible. So every new year, I always have to anticipate and pay the dreaded cost,” she said.

Mylan offers a My EpiPen Savings Card to help consumers with cost. Last year, nearly 80% of commercially insured patients used the card to receive the device for free, according to Mylan.

The company also has distributed more than 700,000 free EpiPens to schools nationwide.

Additionally, “there are some coupons available, which help lower the cost to patients, but there still is a considerable copay for most patients,” said Casale, the AAAAI executive vice president.

“Although the cost of epinephrine auto injectors has risen considerably, they are lifesaving and patients should do whatever they can to secure them.”

Meanwhile, Kesselheim and his colleagues suggested short-term strategies to reducing high drug prices in their paper.

“We need to re-examine the market exclusivities provided by the government to manufacturers to ensure that they adequately protect innovative products without similarly applying to less innovative treatments that add cost without adding value,” Kesselheim said.

“More patients and physicians need to talk about the costs of medications with each other — and express concern to their legislators — so that evidence-based lower-cost alternatives can be found, if possible.”