Home Drug Guide Estradiol; Norethindrone Acetate; Relugolix

Drug Guide

Generic Name

Estradiol; Norethindrone Acetate; Relugolix

Brand Names Myfembree

Classification

Therapeutic: Hormonal therapy for uterine fibroids and heavy menstrual bleeding

Pharmacological: Combination hormonal therapy (Estrogen and Progestin) with GnRH receptor antagonist

FDA Approved Indications

Treatment of heavy menstrual bleeding associated with uterine fibroids in women of reproductive age

Mechanism of Action

Estradiol provides estrogen replacement; Norethindrone Acetate is a progestin that counteracts estrogen's proliferative effects on the uterine lining; Relugolix is a GnRH receptor antagonist that decreases gonadotropin release, leading to decreased estrogen and progesterone levels, resulting in reduced fibroid size and bleeding.

Dosage and Administration

Adult: As prescribed, typically involving complex dosing schedules for hormonal therapy; specifics depend on clinical protocols.

Pediatric: Not indicated for pediatric use.

Geriatric: Use with caution; assess effectiveness and adverse effects in older women.

Renal Impairment: Adjustments may be necessary; consult specific product labeling.

Hepatic Impairment: Use with caution; liver function should be monitored.

Pharmacokinetics

Absorption: Rapid absorption following oral administration.

Distribution: Widely distributed; serum albumin and sex hormone-binding globulin influence binding.

Metabolism: Extensively metabolized in the liver via CYP enzymes.

Excretion: Metabolites are excreted primarily in feces and urine.

Half Life: Relugolix approximately 25 hours; Estradiol and Norethindrone half-lives vary.

Contraindications

Active or recent history of thromboembolic disorders.
Known or suspected breast cancer.
Undiagnosed abnormal uterine bleeding.
Pregnancy.

Precautions

Monitor for thromboembolic events, cardiovascular risks, and hepatic impairment. Use caution in women with hormonal-sensitive cancers or liver disease.

Adverse Reactions - Common

Hot flashes (Common)
Headache (Common)
Nausea (Common)

Adverse Reactions - Serious

Venous thromboembolism (Serious)
Liver dysfunction (Serious)
Bone density loss (with long-term GnRH antagonist use) (Serious)

Drug-Drug Interactions

Anticoagulants, corticosteroids, drugs affecting CYP enzymes.

Drug-Food Interactions

N/A

Drug-Herb Interactions

St. John's Wort, other herbal remedies that affect CYP enzymes.

Nursing Implications

Assessment: Monitor bleeding patterns, blood pressure, liver function tests, and signs of thromboembolism.

Diagnoses:

Risk for thromboembolic events
Ineffective tissue perfusion related to clot formation.

Implementation: Administer as prescribed; educate on side effects.

Evaluation: Assess bleeding patterns, adverse effects, and compliance.

Patient/Family Teaching

Take medication exactly as prescribed.
Report symptoms of thromboembolism (leg swelling, chest pain).
Use contraception if applicable; discuss pregnancy safety.
Attend regular follow-ups for monitoring.

Special Considerations

Black Box Warnings:

Thromboembolic disorders, increased risk of cardiovascular events.

Genetic Factors: Consider genetic predispositions affecting clotting.

Lab Test Interference: May affect liver function tests and hormone levels.

Overdose Management

Signs/Symptoms: Nausea, vomiting, abdominal pain, uterine bleeding.

Treatment: Supportive care; consider gastric lavage, activated charcoal, and symptomatic treatment.

Storage and Handling

Storage: Store at room temperature, 20–25°C (68–77°F).

Stability: Stable when stored properly; check expiration date.