FDA Approved Myfembree to Treat Bleeding from Uterine Fibroids

Heavy monthly bleeding is quite a common problem that affects about 1 out of every 5 American women who menstruate. It could mean that your bleeding lasts for more than seven days at a time, and you need to change tampons or pads more often than every two hours, or you pass clots larger than the size of the quarter. There are multiple causes for this, but one possible explanation for heavy monthly bleeding is uterine fibroids.

Meaning of uterine fibroids

Uterine fibroids or fibroids are non-cancerous tumors that grow around and in the uterus. Anyone with internal reproductive organs is likely to experience it. The estimates suggest 20% and 80% of people who menstruate before 50 are prone to get fibroids.

Apart from heavy bleeding, fibroids are likely to cause lower back pain, the feeling of fullness around the genitals and hips, and complications during pregnancy.

There are multiple ways to treat heavy bleeding due to fibroids, but recently Myovant Sciences and Pfizer announced the FDA approval of Myfembree. It is the first once-daily medication to get approval for treating fibroid symptoms in people who menstruate.

What is Myfembree?

Myfembree is a combination of three medications: norethindrone acetate, estradiol, and relugolix. It is available once-daily oral tablet that you can take without or with food.

You should begin your first Myfembree prescription within seven days of the start of your monthly bleeding. Once you start to take it, you will take it every day until the provider asks you to stop.

How does Myfembree work?

Relugolix belongs to a group of medications called gonadotropin-releasing hormone (GnRH) antagonists. It attaches to an area of your brain that signals the body to produce progesterone and estrogen. These two hormones are responsible for a person’s monthly bleeding cycle. Once relugolix starts to work, your body will produce less of these hormones, and you will experience less monthly bleeding.

Estradiol is a synthetic (lab-made) estrogen. Even though it may seem like taking an estrogen along with relugolix would cause opposite effects, estradiol plays a crucial role. The reason is that relugolix lowers your natural estrogen when you are at high risk for bone loss. Estradiol also helps to prevent side effects. It provides your body with some of the estrogens to keep your bones healthy.

Norethindrone acetate is a kind of progestin-synthetic progesterone. To take a progestin, may seem to counteract relugolix’s effects, but it doesn’t. If you have a uterus and take a form of estrogen-like estradiol, it is essential that you also take progestin. Estrogen alone will raise the risk of developing progestins and endometrial cancer as it helps to lower that risk.

Effectiveness of Myfembree

During the phase 3 clinical trials, the last step before the manufacturers seek FDA approval – Myfembree helps relieve heavy bleeding for over 70% of people who took it. On average, people reported 84% less bleeding after they took Myfembree. 50% of the participant who took medications stopped experiencing monthly bleeding altogether.

How safe is Myfembree?

Just like all the hormonal treatments, Myfembree comes with few risks. One of the biggest warnings is that the medication may result in bone loss, and you need to take it in case of osteoporosis. As mentioned earlier, the relugolix in Myfembree lowers down the level of natural estrogen in your body. It plays a crucial role in keeping the bones healthy. Because of the serious side effect, you must only take Myfembree for a total of two years. You need bone density checked before you take it.

Another side effect of Myfembree is a higher risk of blood clots. All the medicines contain a form of estrogen that carries this risk. However, clinical trials for Myfembree suggest the risk is lower in this medication.

Out of more than 1000 people who took the medication during the studies, only one person developed blood clots. The person also had other risk factors for blood clots, that is why you must discuss your blood clot risks with your provider before you take Myfembree.

Other side effects of Myfembree

Myfembree was well-tolerated in studies. The most common side effects are:


Myfembree is a combination medicine that was recently FDA-approved to treat heavy monthly bleeding caused by uterine fibroids. In studies, it was very effective with few side effects, but it does carry some serious risks, including a high risk for bone clots and bone loss. It is best to discuss the risks for complications with the doctor before you take the medication.

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