Relugolix, Estradiol Hemihydrate, and Norethindrone Acetate is a prescription medicine (Gonadotropin Releasing Hormone Receptor Antagonist). The sections below reproduce one FDA label for it, named under "Label". Products in other forms, strengths or from other makers have their own labels, which can differ.
- Type
- Prescription only (Rx)
- Brand names
- Myfembree
- Drug class
- Gonadotropin Releasing Hormone Receptor Antagonist
- Taken
- Oral
- Label
- Sumitomo Pharma America, Inc, revised September 4, 2025 · full label on DailyMed
- Generic
- No · details
Boxed warning — the FDA's most serious warning for a medicine
WARNING: THROMBOEMBOLIC DISORDERS AND VASCULAR EVENTS Estrogen and progestin combinations, including MYFEMBREE, increase the risk of thrombotic or thromboembolic disorders including pulmonary embolism (PE), deep vein thrombosis (DVT), stroke and myocardial infarction (MI), especially in women at increased risk for these events [see Warnings and Precautions ( 5.1 )]. MYFEMBREE is contraindicated in women with current or a history of thrombotic or thromboembolic disorders and in women at increased risk for these events, including women over 35 years of age who smoke or women with uncontrolled hypertension [see Contraindications ( 4 )]. WARNING: THROMBOEMBOLIC DISORDERS AND VASCULAR EVENTS See full prescribing information for complete boxed warning Estrogen and progestin combinations, including MYFEMBREE, increase the risk of thrombotic or thromboembolic disorders, especially in women at increased risk for these events. ( 5.1 ) MYFEMBREE is contraindicated in women with current or a history of thrombotic or thromboembolic disorders and in women at increased risk for these events, including women over 35 years of age who smoke or women with uncontrolled hypertension. ( 4 )
What it is used for
MYFEMBREE is a combination of relugolix, a gonadotropin-releasing hormone (GnRH) receptor antagonist, estradiol, an estrogen, and norethindrone acetate, a progestin, indicated in premenopausal women for the: management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids). ( 1.1 , 14.1 ) management of moderate to severe pain associated with endometriosis. ( 1.2 , 14.2 ) Limitations of Use Use of MYFEMBREE should be limited to 24 months due to the risk of continued bone loss which may not be reversible. ( 1.3 , 5.2 , 6 )
1.1 Heavy Menstrual Bleeding Associated with Uterine Leiomyomas MYFEMBREE is indicated for the management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids) in premenopausal women [ see Clinical Studies ( 14 ) ].
1.2 Moderate to Severe Pain Associated with Endometriosis MYFEMBREE is indicated for the management of moderate to severe pain associated with endometriosis in premenopausal women [ see Clinical Studies ( 14 ) ].
1.3 Limitations of Use Use of MYFEMBREE should be limited to 24 months due to the risk of continued bone loss that may not be reversible [see Warnings and Precautions ( 5.2 ) and Adverse Reactions ( 6 )].
Forms and strengths
Tablets: Each tablet of MYFEMBREE contains a fixed-dose combination of relugolix 40 mg, estradiol (E2) 1 mg, and norethindrone acetate (NETA) 0.5 mg. The tablets are light yellow to yellow, round, film-coated, and debossed with “MVT” on one side and “415” on the other side. Tablets: fixed-dose combination containing relugolix 40 mg, estradiol 1 mg and norethindrone acetate 0.5 mg. ( 3 )
Who should not take it (contraindications)
MYFEMBREE is contraindicated in women: With a high risk of arterial, venous thrombotic, or thromboembolic disorders [see Boxed Warning and Warnings and Precautions ( 5.1 )] . Examples include women over 35 years of age who smoke and women who are known to have: current or history of deep vein thrombosis or pulmonary embolism vascular disease (e.g., cerebrovascular disease, coronary artery disease, peripheral vascular disease) thrombogenic valvular or thrombogenic rhythm diseases of the heart (e.g., subacute bacterial endocarditis with valvular disease, or atrial fibrillation) inherited or acquired hypercoagulopathies uncontrolled hypertension headaches with focal neurological symptoms or migraine headaches with aura if over 35 years of age Who are pregnant. Exposure to MYFEMBREE early in pregnancy may increase the risk of early pregnancy loss [see Warnings and Precautions ( 5.9 ) and Use in Specific Populations ( 8.1 )] . With known osteoporosis, because of the risk of further bone loss [see Warnings and Precautions ( 5.2 )]. With current or history of breast cancer or other hormone-sensitive malignancies, and with increased risk for hormone-sensitive malignancies [see Warnings and Precautions ( 5.3 )] . With known hepatic impairment or disease [see Warnings and Precautions ( 5.5 )] . With undiagnosed abnormal uterine bleeding. With known anaphylactic reaction, angioedema, or hypersensitivity to MYFEMBREE or any of its components. Anaphylactoid reactions, urticaria, and angioedema have been reported [see Warnings and Precautions ( 5.14 ), Adverse Reactions ( 6.2 )]. High risk of arterial, venous thrombotic, or thromboembolic disorder. ( 4 ) Pregnancy. ( 4 ) Known osteoporosis. ( 4 ) Current or history of breast cancer or other hormone-sensitive malignancies. ( 4 ) Known hepatic impairment or disease. ( 4 ) Undiagnosed abnormal uterine bleeding. ( 4 ) Known hypersensitivity to components of MYFEMBREE. ( 4 )
Warnings and precautions
Thromboembolic Disorders and Vascular Events : Discontinue MYFEMBREE if an arterial or venous thrombotic, cardiovascular, or cerebrovascular event occurs. Discontinue MYFEMBREE if there is sudden unexplained partial or complete loss of vision, proptosis, diplopia, papilledema, or retinal vascular lesions and evaluate for retinal vein thrombosis immediately. ( 5.1 ) Bone Loss : Decreases in bone mineral density (BMD) may not be completely reversible. Baseline BMD assessment is recommended in all women. In women with heavy menstrual bleeding associated with uterine fibroids, periodic BMD assessments are recommended. In women with moderate to severe pain associated with endometriosis, annual BMD assessments are recommended. Assess risk-benefit for women with additional risk factors for bone loss. ( 5.2 ) Suicidal Ideation and Mood Disorders (Including Depression) : Advise patients to seek medical attention for new onset or worsening depression, anxiety, or other mood changes. ( 5.4 ) Hepatic Impairment and Transaminase Elevations : Counsel patients on signs and symptoms of liver injury. ( 5.5 ) Elevated Blood Pressure : Do not use in women with uncontrolled hypertension. For women with well-controlled hypertension, continue to monitor blood pressure and stop MYFEMBREE if blood pressure rises significantly. ( 5.7 ) Change in Menstrual Bleeding Pattern and Reduced Ability to Recognize Pregnancy : Advise women to use non-hormonal contraception during treatment and for one week after discontinuing MYFEMBREE. MYFEMBREE may delay the ability to recognize pregnancy because it alters menstrual bleeding. Perform testing if pregnancy is suspected and discontinue MYFEMBREE if pregnancy is confirmed. ( 5.8 ) Risk of Early Pregnancy Loss : Can cause early pregnancy loss. Advise women to use effective non-hormonal contraception. ( 5.9 ) Uterine Fibroid Prolapse or Expulsion : Advise patients to seek medical attention for severe uterine bleeding. ( 5.10 ) Hypersensitivity Reactions : Immediately discontinue MYFEMBREE if a hypersensitivity reaction occurs. ( 5.14 )
5.1 Thromboembolic Disorders and Vascular Events MYFEMBREE is contraindicated in women with current or history of thrombotic or thromboembolic disorders and in women at increased risk for these events [see Contraindications ( 4 )] . Discontinue MYFEMBREE immediately if an arterial or venous thrombotic, cardiovascular, or cerebrovascular event occurs or is suspected. Discontinue MYFEMBREE at least 4 to 6 weeks before surgery of the type associated with an increased risk of thromboembolism, or during periods of prolonged immobilization, if feasible. Discontinue MYFEMBREE immediately if there is sudden unexplained partial or complete loss of vision, proptosis, diplopia, papilledema, or retinal vascular lesions and evaluate for retinal vein thrombosis as these have been reported in patients receiving estrogens and progestins. Estrogen and progestin combinations, including the estradiol/norethindrone acetate component of MYFEMBREE, increase the risk of thrombotic or thromboembolic disorders, including pulmonary embolism, deep vein thrombosis, stroke, and myocardial infarction, especially in women at high risk for these events. In general, the risk is greatest among women over 35 years of age who smoke and women with uncontrolled hypertension, dyslipidemia, vascular disease, or obesity. Two thromboembolic events (DVT and PE) occurred in one woman treated for 38 days with MYFEMBREE for moderate to severe pain associated with endometriosis.
5.2 Bone Loss MYFEMBREE is contraindicated in women with known osteoporosis [see Contraindications ( 4 )]. Consider the benefits and risks of MYFEMBREE treatment in patients with a history of a low trauma fracture or risk factors for osteoporosis or bone loss, including taking medications that may decrease bone mineral density (BMD) (e.g., systemic or chronic inhaled corticosteroids, anticonvulsants, or chronic use of proton pump inhibitors). Assessment of BMD by dual-energy X-ray absorptiometry (DXA) is recommended at baseline. In women with heavy menstrual bleeding associated with uterine fibroids, periodic DXA during treatment with MYFEMBREE is recommended. In women with moderate to severe pain associated with endometriosis, annual DXA is recommended while taking MYFEMBREE. Consider discontinuing MYFEMBREE if the risk associated with bone loss exceeds the potential benefit of treatment. Although the effect of supplementation with calcium and vitamin D was not studied, such supplementation for patients with inadequate dietary intake may be beneficial. MYFEMBREE may cause a decrease in BMD in some patients. BMD loss may be greater with increasing duration of use and may not be completely reversible after stopping treatment [see Adverse Reactions ( 6.1 )] . The impact of BMD decreases on long-term bone health and future fracture risk in premenopausal women is unknown.
5.3 Hormone-Sensitive Malignancies MYFEMBREE is contraindicated in women with current or a history of hormone-sensitive malignancies (e.g., breast cancer) and in women at increased risk for hormone-sensitive malignancies [see Contraindications ( 4 )] . Discontinue MYFEMBREE if a hormone-sensitive malignancy is diagnosed. Surveillance measures in accordance with standard of care, such as breast examinations and mammography, are recommended. The use of estrogen alone or estrogen plus progestin has been reported to result in an increase in abnormal mammograms requiring further evaluation.
5.4 Suicidal Ideation and Mood Disorders (Including Depression) Evaluate patients with a history of suicidal ideation, depression, and mood disorders prior to initiating treatment. Monitor patients for mood changes and depressive symptoms including shortly after initiating treatment, to determine whether the risks of continuing therapy with MYFEMBREE outweigh the benefits. Patients with new or worsening depression, anxiety, or other mood changes should be referred to a mental health professional, as appropriate. Advise patients to seek immediate medical attention for suicidal ideation and behavior. Re-evaluate the benefits and risks of continuing MYFEMBREE if such events occur. Gonadotropin-releasing hormone receptor antagonists, including MYFEMBREE, have been associated with mood disorders (including depression) and suicidal ideation. In Studies L1 and L2 in women with heavy menstrual bleeding associated with uterine fibroids, a greater proportion of women treated with MYFEMBREE compared with placebo reported depression (including depression, mood swings, and depressed mood) (2.4% vs. 0.8%), irritability (2.4% vs. 0%), and anxiety (1.2% vs. 0.8%) [see Adverse Reactions ( 6.1 )] . In Studies S1 and S2 in women with moderate to severe pain associated with endometriosis, a greater proportion of women treated with MYFEMBREE as compared to placebo reported mood disorders (including depression) (9.1% vs. 7.2%). In addition, cases of suicidal ideation were reported with MYFEMBREE use. All women who reported suicidal ideation had a history of depression and/or anxiety [see Adverse Reactions ( 6.1 )] .
5.5 Hepatic Impairment and Transaminase Elevations Contraindication in Patients with Hepatic Impairment MYFEMBREE is contraindicated in patients with known hepatic impairment or disease [see Contraindications ( 4 ) and Use in Specific Populations ( 8.6 )] . Steroid hormones may be poorly metabolized in patients with impaired liver function [see Clinical Pharmacology ( 12.3 )]. Transaminase Elevations Instruct women to promptly seek medical attention for symptoms or signs that may reflect liver injury, such as jaundice or right upper abdominal pain. Acute liver test abnormalities may necessitate the discontinuation of MYFEMBREE use until the liver tests return to normal and MYFEMBREE causation has been excluded. […]
Side effects (adverse reactions)
The following clinically significant adverse reactions are discussed elsewhere in the labeling: Thromboembolic Disorders and Vascular Events [see Warnings and Precautions ( 5.1 )] Bone Loss [see Warnings and Precautions ( 5.2 )] Suicidal Ideation and Mood Disorders (Including Depression) [see Warnings and Precautions ( 5.4 )] Hepatic Impairment and Transaminase Elevations [see Warnings and Precautions ( 5.5 )] Elevated Blood Pressure [see Warnings and Precautions ( 5.7 )] Change in Menstrual Bleeding Pattern and Reduced Ability to Recognize Pregnancy [see Warnings and Precautions ( 5.8 )] Uterine Fibroid Prolapse or Expulsion [see Warnings and Precautions ( 5.10 )] Alopecia [see Warnings and Precautions ( 5.11 )] Effects on Carbohydrate and Lipid Metabolism [see Warnings and Precautions ( 5.12 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.14 )] In women with heavy menstrual bleeding associated with uterine fibroids, most common adverse reactions (incidence ≥ 3%) are vasomotor symptoms, uterine bleeding, alopecia, and decreased libido. In women with moderate to severe pain associated with endometriosis, most common adverse reactions (incidence ≥ 3%) are headache, vasomotor symptoms, mood disorders, abnormal uterine bleeding, nausea, toothache, back pain, decreased sexual desire and arousal, arthralgia, fatigue, and dizziness. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Sumitomo Pharma America, Inc. at 1-833-696-8268 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Heavy Menstrual Bleeding Associated with Uterine Leiomyomas The safety of MYFEMBREE was evaluated in two placebo-controlled clinical trials, Study L1 (LIBERTY 1) and Study L2 (LIBERTY 2), in women with heavy menstrual bleeding associated with uterine fibroids. In these trials, women received a once daily relugolix 40-mg tablet and an over-encapsulated tablet of E2 1 mg and NETA 0.5 mg (relugolix + E2/NETA), which is equivalent to 1 tablet of MYFEMBREE. Across the two trials, 254 women received MYFEMBREE once daily for 24 weeks. Additionally, 256 women received placebo for 24 weeks, and 258 women received relugolix 40-mg monotherapy once daily for 12 weeks followed by MYFEMBREE for 12 weeks [see Clinical Studies ( 14.1 )] . Of these, 476 women were treated with MYFEMBREE in a 28-week extension trial, Study L3 (LIBERTY Extension), for a total treatment duration of up to 12 months. Demographics were similar across the studies; approximately 43% were White, 51% were Black, and approximately 23% were of Hispanic or Latino ethnicity. The mean age at study entry was approximately 42 years (range 19 to 51 years). Of women who completed Study L3, 229 were rerandomized to continue MYFEMBREE or withdraw from therapy (placebo) for an additional 52 weeks (Study L4). Serious Adverse Reactions In Studies L1 and L2, serious adverse reactions were reported in 3.1% of MYFEMBREE-treated women as compared to 2.3% of placebo-treated women. In MYFEMBREE-treated women, serious adverse drug reactions included uterine myoma expulsion and menorrhagia experienced by one woman and uterine leiomyoma (prolapse), cholecystitis, and pelvic pain reported for one woman each. Adverse Reactions Leading to Study Drug Discontinuation In Studies L1 and L2, 3.9% of women treated with MYFEMBREE discontinued therapy due to adverse reactions, as compared to 4.3% receiving placebo. The most common adverse reaction leading to discontinuation of MYFEMBREE was uterine bleeding (1.2%) with an onset usually reported within the first 3 months of therapy. Common Adverse Reactions The most common adverse reactions reported in at least 3% of women treated with MYFEMBREE for heavy menstrual bleeding associated with uterine fibroids and at an incidence greater than placebo during double-blind placebo-controlled treatment are summarized below in Table 1 . Table 1: Adverse Reactions Occurring in 3% or More in Women with Heavy Menstrual Bleeding Associated with Uterine Fibroids Treated with MYFEMBREE in Studies L1 and L2 1 Includes hot flush, hyperhidrosis, or night sweats. 2 Includes menorrhagia, metrorrhagia, vaginal hemorrhage, polymenorrhea, and menstruation irregular. 3 Includes libido decreased and loss of libido. Adverse Reaction MYFEMBREE (N = 254) % Placebo (N = 256) % Vasomotor symptoms 1 10.6
6.6 Abnormal uterine bleeding 2 6.3
1.2 Alopecia 3.5
0.8 Libido decreased 3 3.1
0.4 In Study L1, more women experienced the adverse reaction of new or worsening hypertension with MYFEMBREE as compared to placebo (7.0% vs. 0.8%). The most common adverse reactions reported during the extension trial, Study L3, were similar to those reported in the placebo-controlled trials. Less Common Adverse Reactions Adverse reactions reported in at least 2% and less than 3% of women with heavy menstrual bleeding associated with uterine fibroids in the MYFEMBREE treated group and greater incidence than placebo included irritability, dyspepsia, and breast cyst. Other important adverse reactions reported in MYFEMBREE-treated women included one serious reaction each of uterine myoma expulsion (0.4%) and uterine leiomyoma (prolapse) (0.4%). Bone Loss The effect of MYFEMBREE on BMD was assessed by DXA. The least squares mean percent changes from baseline in lumbar spine BMD at Month 6 in Studies L1 and L2 are presented below in Table 2 . Table 2: Mean Percent Change (On-Treatment) from Baseline in Lumbar Spine BMD in Women with Heavy Menstrual Bleeding Associated with Uterine Fibroids in Studies L1 and L2 at Month 6 Abbreviations: BMD = bone mineral density; CI = confidence interval. MYFEMBREE Placebo Number of subjects 254 256 Percent change from baseline (95% CI) -0.23 (-0.64, 0.18) 0.18 (-0.21, 0.58) Treatment difference, % -0.42 In the open-label extension trial, Study L3, women received an additional 28 weeks of MYFEMBREE for a total of up to 52 weeks of treatment. Women from Study L3 showed continued bone loss at Months 6 and 12 when treated with up to 52 weeks of MYFEMBREE. The least squares mean percent changes from baseline in lumbar spine BMD at Months 6 and 12 are presented below in Table 3 . Table 3: Mean Percent Change (On-Treatment) from Baseline* in Lumbar Spine BMD at Month 6* and Month 12 for MYFEMBREE-Treated Women with Heavy Menstrual Bleeding Associated with Uterine Fibroids in Study L3 Abbreviations: BMD = bone mineral density; CI = confidence interval. * Baseline and Month 6 assessments include only those participants from Studies L1 and L2 who participated in Study L3. Number of Women (N = 163) Month 6* Month 12 Percent change from baseline* (95% CI) -0.23 (-0.69, 0.24) -0.80 (-1.36, -0.25) A separate concurrent prospective observational study enrolled 262 women with heavy menstrual bleeding associated with uterine fibroids who were age-matched to participants of Studies L1 and L2. While these women were not randomized to receive treatment for heavy menstrual bleeding associated with uterine fibroids, women were permitted to receive treatment from their provider during the clinical trials for this indication. Women underwent DXA scans at baseline, Month 6 and Month 12 to monitor for changes in BMD. The mean percent changes from baseline (95% CI) in lumbar spine BMD at Months 6 and 12 were 0.00 (-0.32, 0.31) and -0.41 (-0.77, -0.05), respectively. A decline in lumbar spine BMD of > 3% was observed in 23% (30/132) of women who had a DXA scan following 12 months of MYFEMBREE treatment in Study L3 and in 17.4% (37/213) of untreated women in the Observational Uterine Fibroids Cohort. […]
Drug interactions
Avoid use of MYFEMBREE with oral P-gp inhibitors. ( 7.1 ) Avoid use with combined P-gp and strong CYP3A inducers, as the exposure of the components of MYFEMBREE may be decreased. ( 7.1 )
7.1 Effect of Other Drugs on MYFEMBREE P-gp Inhibitors Co-administration of MYFEMBREE with P-gp inhibitors increases the AUC and maximum concentration (C max ) of relugolix [see Clinical Pharmacology ( 12.3 )] and may increase the risk of adverse reactions associated with MYFEMBREE. Avoid use of MYFEMBREE with oral P-gp inhibitors. If use is unavoidable, take MYFEMBREE first, separate dosing by at least 6 hours, and monitor patients for adverse reactions [see Dosage and Administration ( 2.4 )] . Combined P-gp and Strong CYP3A Inducers Use of MYFEMBREE with combined P-gp and strong CYP3A inducers decreases the AUC and C max of relugolix, estradiol, and/or norethindrone [see Clinical Pharmacology ( 12.3 )] and may decrease the therapeutic effects of MYFEMBREE. Avoid use of MYFEMBREE with combined P-gp and strong CYP3A inducers.
Pregnancy, breastfeeding, children and older adults
8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to MYFEMBREE during pregnancy. Pregnant females exposed to MYFEMBREE and healthcare providers are encouraged to call the MYFEMBREE Pregnancy Exposure Registry at 1-855-428-0707. Risk Summary MYFEMBREE is contraindicated in pregnancy [see Contraindications ( 4 ) and Warnings and Precautions ( 5.9 )]. Based on findings from animal studies and its mechanism of action, MYFEMBREE may cause early pregnancy loss. Discontinue MYFEMBREE if pregnancy occurs during treatment [see Warnings and Precautions ( 5.9 ) and Clinical Pharmacology ( 12.1 )] . The limited human data with the use of MYFEMBREE in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes [see Data ]. In animal reproduction studies, oral administration of relugolix in pregnant rabbits during organogenesis resulted in spontaneous abortion and total litter loss at relugolix exposures about half those at the maximum recommended human dose (MRHD) of 40 mg. In both rabbits and rats, no fetal malformations were present at any dose level tested which were associated with relugolix exposures about half and approximately 300 times exposures in women at the MRHD, respectively [see Data ]. Epidemiologic studies and meta-analyses have not found an increased risk of genital or non-genital birth defects (including cardiac anomalies and limb-reduction defects) following exposure to estrogens and progestins before conception or during early pregnancy. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. There are insufficient data to conclude whether the presence of uterine fibroids or endometriosis reduces the likelihood of achieving pregnancy or increases the risk of adverse pregnancy outcomes. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the United States general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2% to 4% and 15% to 20%, respectively. Data Animal Data In an embryo-fetal development study, oral administration of relugolix to pregnant rabbits during the period of organogenesis (Days 6 to 18 of gestation) resulted in abortion, total litter loss, or decreased number of live fetuses at a dose of 9 mg/kg/day (about half the human exposure at the maximum recommended human dose [MRHD] of 40 mg daily, based on AUC). No treatment related malformations were observed in surviving fetuses. No treatment related effects were observed at 3 mg/kg/day (about 0.1-fold the MRHD) or lower. The binding affinity of relugolix for rabbit GnRH receptors is unknown. In a similar embryo-fetal development study, oral administration of relugolix to pregnant rats during the period of organogenesis (Days 6 to 17 of gestation) did not affect pregnancy status or fetal endpoints at doses up to 1000 mg/kg/day (300 times the MRHD), a dose at which maternal toxicity (decreased body weight gain and food consumption) was observed. A no observed adverse effect level (NOAEL) for maternal toxicity was 200 mg/kg/day (86 times the MRHD). In rats, the binding affinity of relugolix for GnRH receptors is more than 1000-fold lower than that in humans, and this study represents an assessment of non-pharmacological targets of relugolix during pregnancy. No treatment related malformations were observed up to 1000 mg/kg/day. In a pre- and postnatal developmental study in pregnant and lactating rats, oral administration of relugolix to rats during late pregnancy and lactation (Day 6 of gestation to Day 20 of lactation) had no effects on pre- and postnatal development at doses up to 1000 mg/kg/day (300 times the MRHD), a dose in which maternal toxicity was observed (effects on body weight gain). A NOAEL for maternal toxicity was 100 mg/kg/day (34 times the MRHD).
8.2 Lactation Risk Summary Detectable amounts of estrogen and progestin have been identified in the breast milk of women receiving estrogen plus progestin therapy and can reduce milk production in breast-feeding women. This reduction can occur at any time but is less likely to occur once breast-feeding is well established. Relugolix was detected in human breast milk. In a single dose milk-only lactation study in 8 healthy adult lactating women, the mean total amount of relugolix recovered in human breast milk over the first 24 hours was 0.0031 mg and over 120 hours (5 days) was 0.0042 mg following a single, oral, maternal dose of 40 mg. The mean calculated daily infant dose was 0.0006 mg/kg/day using 0.0031mg (the amount recovered in human breast milk over the first 24 hours). The relative infant dose was 0.105% of the maternal weight-adjusted dose of 40 mg. There are no data on the effects of relugolix or its metabolites on the breastfed child, or the effects on milk production. The developmental and health benefits of breast-feeding should be considered along with the mother's clinical need for MYFEMBREE and any potential adverse effects on the breastfed child from MYFEMBREE or from the underlying maternal condition.
8.3 Females and Males of Reproductive Potential Based on animal data and the mechanism of action, MYFEMBREE can cause early pregnancy loss if MYFEMBREE is administered to pregnant women [see Use in Specific Populations ( 8.1 )]. Pregnancy Testing MYFEMBREE may delay the ability to recognize pregnancy because it may reduce the intensity, duration, and amount of menstrual bleeding [see Warnings and Precautions ( 5.8 )]. Exclude pregnancy before initiating treatment with MYFEMBREE. Perform pregnancy testing if pregnancy is suspected during treatment with MYFEMBREE and discontinue treatment if pregnancy is confirmed [see Contraindications ( 4 ) and Warnings and Precautions ( 5.8 )]. Contraception Advise women of reproductive potential to use effective non-hormonal contraception during treatment with MYFEMBREE and for at least 1 week following discontinuation. Avoid concomitant use of hormonal contraceptives with MYFEMBREE. The use of estrogen-containing hormonal contraceptives may increase the risk of estrogen-associated adverse events and is expected to decrease the efficacy of MYFEMBREE [see Warnings and Precautions ( 5.8 ) ] .
8.4 Pediatric Use Safety and effectiveness of MYFEMBREE in pediatric patients have not been established.
8.6 Hepatic Impairment MYFEMBREE is contraindicated in women with hepatic impairment or disease [see Contraindications ( 4 )]. The use of E2 (a component of MYFEMBREE) in patients with hepatic impairment is expected to increase the exposure to E2 and increase the risk of E2-associated adverse reactions [see Clinical Pharmacology ( 12.3 )] .
How it works
MYFEMBREE is a combination of relugolix, estradiol (E2), and norethindrone acetate (NETA). Relugolix is a non-peptide GnRH receptor antagonist that competitively binds to pituitary GnRH receptors, thereby reducing the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to decreased serum concentrations of the ovarian sex hormones estradiol and progesterone and reduced bleeding associated with uterine fibroids and pain associated with endometriosis. Estradiol acts by binding to nuclear receptors that are expressed in estrogen-responsive tissues. As a component of MYFEMBREE, the addition of exogenous estradiol may reduce the increase in bone resorption and resultant bone loss that can occur due to a decrease in circulating estrogen concentrations from relugolix alone. Progestins such as norethindrone act by binding to nuclear receptors that are expressed in progesterone-responsive tissues. As a component of MYFEMBREE, norethindrone may protect the uterus from the potential adverse endometrial effects of unopposed estrogen.
Is there a generic Relugolix, Estradiol Hemihydrate, and Norethindrone Acetate?
No. The FDA has not approved a generic version yet.
Brand-name versions
- Myfembree Sumitomo Pharma Am, approved 2021
Source: Drugs@FDA (via openFDA), checked October 29, 2026. Marketing status is what companies report to the FDA; whether a pharmacy stocks a product, and what your insurance covers, can differ.
Dosage:
we do not reproduce dosing instructions. The right dose depends on the person and the condition and is set by the prescriber or pharmacist. Dosage section of the full label.
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Source: FDA structured product labeling, retrieved through openFDA. Label text is shown as published by the FDA, without editing; long sections are shortened, marked […]. openFDA data are not validated for clinical use — always check the current label and ask a doctor or pharmacist about your own treatment. Set ID fc3feb73-cc84-43a8-aa32-b262460495e8.