The Food and Drug Administration announced Friday it has approved a new kind of drug to treat moderate to severe hot flashes caused by menopause, which could offer relief to millions of women who do not want to take hormone therapy to treat their symptoms.

Drugmaker Astellas says the pills — fezolinetant, branded as Veozah — could be available in pharmacies within three weeks. The drug is taken once a day. 

It works to block a chemical in the brain that affects how the body’s temperature is regulated. The company touts the drug as a milestone in addressing the root cause of what doctors call menopause’s vasomotor symptoms.

As many as 80% of women face hot flashes as they age into their 40s and 50s. Some can manage them with simple lifestyle changes, like avoiding alcohol and dressing in layers.

But hot flashes can be debilitating for some, with rapid and unpredictable episodes forcing women to miss work and upending their lives. Up to 46% of women experienced moderate or severe hot flashes for years, one study found.

“Hot flashes as a result of menopause can be a serious physical burden on women and impact their quality of life,” the FDA’s Dr. Janet Maynard said in a statement announcing the approval. 

Fezolinetant is not the first drug approved by the FDA to treat menopause, but it is different from those that came before. 

For decades, hormone replacement therapy has been the treatment recommended by experts for severe symptoms from menopause. 

But use of those treatments fell sharply after results from the government-backed Women’s Health Initiative in 2002 suggested taking a combination of estrogen and progestin might raise the risk of worrying conditions like breast cancer and heart disease. 

That led to experts tailoring their guidance, though they say evidence shows that the benefits still outweigh the risks for many women struggling with symptoms.

An antidepressant, paroxetine, is the main non-hormonal treatment alternative available for women. But its approval was controversial and experts consider it to be less effective.

While true head-to-head studies have not been published comparing fezolinetant against menopausal hormone therapy, or MHT, research so far on the drug suggests it could be a promising alternative.

“Over the short-term, the safety and tolerability of fezolinetant and MHT appear comparable. However, longer term use of MHT carries serious increased risks,” wrote the Institute for Clinical and Economic Review in a report last year.

Other options could be available soon for this market, which Astellas estimated in 2016 could be as much as $1 billion. Drugmaker Bayer is in the final Phase 3 trials for its drug, called elinzanetant, which takes a similar approach.

“The introduction of a new molecule to treat moderate to severe menopausal hot flashes will provide an additional safe and effective treatment option for women,” Maynard said.