A top inhaler for children was discontinued. Families and doctors are scrambling to fill the gap.

Both her 5-year-old son Burton and her 9-year-old daughter Julianna have asthma. Hayes has poured time, energy, and ink into convincing her insurance company to cover a generic alternative for Burton, while securing a branded alternative for Julianna.

That has provided a limited reprieve that could quickly evaporate. There are shortages of the branded alternative Julianna is using because of high demand, and there’s no guarantee Hayes’ insurance will continue covering Burton’s medication.

Hayes knows the fight is far from over. “It does feel like a game that I don’t have enough energy to play a lot of the time,” she said.

For decades, Flovent was the number one drug prescribed for children with asthma. But suddenly, in January, the inhaler was no longer available, leaving doctors and families in a bind.

Finding the right medicine is still a problem: Flovent is no longer being produced, many insurance companies don’t cover a generic alternative, and there’s a shortage of a similar branded alternative.

With about 230,000 children with asthma across New Hampshire, Massachusetts, Maine, and Vermont, legislators are now joining in Hayes’ fight.

“This has led to a crisis for children with asthma, leaving families across the country with no way to afford this life-saving medication,” Democratic Senator Maggie Hassan wrote in a letter to the CEO of GlaxoSmithKline, the inhaler’s manufacturer.

Doctors in New England are seeing the consequences, too.

In May, pediatricians at the Children’s Hospital of Philadelphia said they’ve seen a dramatic increase in asthma-related deaths, with admissions for asthma-related problems up 50 percent in March and April compared to last year. Lack of access to basic medications is one factor driving the increase that could be addressed, according to doctors Chén Kenyon, Bianca Nfonoyim Bernhard, and Tyra Bryant-Stephens.

Flovent “has been the first line medicine for pretty much all pediatric pulmonologists to use with kids with asthma, so to have it disappear essentially on Jan. 1 was just awful,” said Brian P. O’Sullivan, a pediatric pulmonologist at Dartmouth Health, who practices in Manchester and Lebanon. “It was just a real setback for us.”

Flovent was pulled from the market by the pharmaceutical company that produced it, GlaxoSmithKline, or GSK, after promising to cap the out-of-pocket cost of inhalers at $35.

Instead, GSK shifted production to another company through a licensing agreement, avoiding required payments to Medicaid for increasing the cost of Flovent significantly more than the rate of inflation, according to Hassan’s letter.

Hassan wrote to GSK’s CEO Emma Walmsley in May urging her to restore affordable access to Flovent. Hassan got involved after doctors wrote to her, explaining that GSK’s profit-driven decision to discontinue Flovent was disastrous for children with asthma.

“Your company appears to be exploiting a licensing agreement with Prasco Laboratories in order to circumvent your public commitments and price-gouge families without access to affordable alternatives to Flovent,” Hassan wrote.

Massachusetts Senator Elizabeth Warren also blasted GSK for its “price-gouging strategy” in a letter to its CEO requesting more information.

“GSK has chosen to abuse the law by removing Flovent HFA from the market entirely, effectively shielding the company from accountability for decades of price hikes,” Warren wrote.

The generic drug produced by Prasco Laboratories is often not covered by insurance, which means families have to pay up to $150 for a single inhaler that used to cost them between $10 to $60 with insurance. O’Sullivan said that while New Hampshire and Massachusetts Medicaid have started covering the generic version, private insurers have not yet done so.

Hassan said GSK’s maneuver “appears to have been designed to evade payments that GSK owed Medicaid.”

Kathleen Quinn, a spokesperson for GSK, said the company had received the letters and is reviewing them. Quinn told the Washington Post the company planned to discontinue Flovent “for some time” before it promised to limit out-of-pocket costs for asthma products.

“That’s unconscionable,” O’Sullivan said.

Inhaled medications like Flovent have been shown to significantly decrease emergency department visits and hospitalizations by helping control the symptoms of asthma. Without the medication, Dartmouth Health nurse Jessica M. Alofs said children need more doctor’s visits, more hospitalizations, and higher doses of steroids than they should have. And, she said, that in turn causes longer term issues.

Air gets into your lungs through a series of little breathing tubes that are like the branches of a tree, where the trachea is the trunk. Tiny breathing tubes bring good air into the lungs and take bad air out. But for people with asthma, those tubes are inflamed and irritated. And when there’s a flare, they can tighten, making it hard to get air through the airways.

Steroids are anti-inflammatory medicines that can be used preventatively to calm the inflammation and keep the airways open. Without preventative medication, O’Sullivan said, asthmatic kids are more likely to end up in the ER where they could rely on stronger, oral steroids like prednisone.

O’Sullivan said doctors relied on Flovent because it was early to market and it worked well. It also had a specific, child-friendly design called a metered-dose inhaler. That allowed children to inhale the medication while breathing normally, as opposed to other inhalers that use a dry powder and require the user to take a deep breath and hold it.

“That’s great if you’re old enough to take a deep breath and really suck it in, but it ain’t gonna work for a little baby, and I still worry about school-aged kids even being able to do it well,” O’Sullivan said. He said that’s also true when it comes to kids with physical disabilities or developmental delays.

Asmanex is one alternative and is a metered-dose inhaler. But it was out of stock within 18 days of Flovent’s discontinuation, according to the New England Pediatric Pulmonary Consortium, which includes doctors from Massachusetts, New Hampshire, Vermont, and Maine.

For Hayes’ daughter, Julianna, who has been using Asmanex, the shortage means her mom is going to have to urge the insurance companies to instead cover the generic alternative made by Prasco.

That time-consuming process has taken over Alofs’ professional life. Alofs said she’s spent so much time on the phone, little time is left to be with patients.

It’s not unusual for insurance companies to not cover a new medication. But that means families who may have paid $10 to $60 for Flovent could now be left paying up to $150 for a single inhaler, used for about a month.

“We know families who are rationing their kids’ inhalers because they can’t afford it,” said Robyn Cohen, a pediatric pulmonologist and director of Boston Medical Center’s Pediatric Pulmonary and Allergy Clinic.

But Cohen said rationing a needed preventative medication can make it more likely children will need to see a doctor or end up hospitalized for asthma attacks, especially during pollen season. She said the issue is further taxing an already burdened health system.

“Phone lines are jammed because nobody can get their inhalers,” said Cohen. “It just has really for several months paralyzed the system.”

Zoe Hastings, who lives in Lawrence, Mass., has two children. Her son has been on asthma medication since he was 3, and Flovent worked well for him. But Hastings said the cost of the medication skyrocketed after Flovent was discontinued, jumping from $10 to $200.

“We couldn’t afford these medications that were hundreds of dollars,” she said.

In the process of switching to a new medication, Hastings said her son got sick. “He got a cough that wouldn’t have happened if he was on his maintenance inhaler,” she said.

Amanda Gokee can be reached at amanda.gokee@globe.com. Follow her @amanda_gokee.