Prometrium is a bioidentical progesterone capsule indicated for use in hormone replacement therapy (HRT) and the management of specific gynecological conditions. As a micronized, oral formulation of natural progesterone, it is chemically identical to the hormone produced by the human corpus luteum. This product is commonly prescribed to counteract estrogen dominance, support endometrial health, and manage symptoms associated with progesterone deficiency. Its evidence-based application makes it a cornerstone in reproductive endocrinology and menopausal management.

Features

• Contains 100 mg or 200 mg micronized progesterone per soft gelatin capsule
• Bioidentical structure identical to endogenous progesterone
• Formulated in peanut oil; supplied in sealed blister packs
• Oral administration with or without food
• Requires prescription; available in 30-, 60-, or 90-count bottles
• Manufactured under cGMP standards; batch-traceable

Benefits

• Reduces risk of endometrial hyperplasia in postmenopausal women with an intact uterus who are receiving estrogen
• Supports luteal phase supplementation in assisted reproductive technology (ART)
• Alleviates symptoms of progesterone deficiency such as irregular menses and anovulation
• May improve sleep quality due to neurosteroid metabolite effects
• Provides a natural hormone option with predictable pharmacokinetics
• Helps maintain pregnancy in cases of corpus luteum deficiency

Common use

Prometrium is primarily used in hormone replacement regimens for menopausal women with an intact uterus to protect against estrogen-induced endometrial hyperplasia. It is also indicated for the treatment of secondary amenorrhea and is used off-label in fertility treatments to support the luteal phase. In some cases, it is prescribed for menstrual irregularity related to oligo-ovulation or anovulation.

Dosage and direction

For postmenopausal women with an intact uterus on conjugated estrogens: 200 mg orally daily for 12 sequential days per 28-day cycle. For secondary amenorrhea: 400 mg orally once daily at bedtime for 10 days. Swallow capsules whole; do not crush or chew. Administration at bedtime is often recommended to minimize dizziness/drowsiness. Dosage adjustments may be necessary based on clinical response, hepatic function, and concomitant medications.

Precautions

Monitor for signs of depression, thrombotic disorders, or visual disturbances. Use with caution in patients with history of depression, epilepsy, migraine, asthma, or cardiac dysfunction. May cause drowsiness; caution against driving or operating machinery until response is known. Regular breast examinations and mammograms are recommended for patients on long-term therapy. Not recommended for use in patients with known peanut or soy allergies.

Contraindications

Known hypersensitivity to progesterone or any component of the formulation; history of or current thrombophlebitis or thromboembolic disorders; missed abortion; undiagnosed abnormal genital bleeding; known or suspected breast cancer; history of hormone-associated carcinoma; severe hepatic dysfunction; and known peanut allergy.

Possible side effect

Common: drowsiness, dizziness, breast tenderness, headache, mood swings. Less common: nausea, fluid retention, hot flashes, depression. Rare but serious: thrombophlebitis, pulmonary embolism, retinal thrombosis, cerebral thrombosis. Allergic reactions including urticaria and anaphylaxis may occur in peanut-allergic individuals.

Drug interaction

Potent CYP3A4 inducers (e.g., rifampin, St. John’s wort) may reduce progesterone levels. CYP3A4 inhibitors (e.g., ketoconazole) may increase levels. May enhance effects of CNS depressants. Concurrent use with other hormonal therapies may require dosage adjustment.

Missed dose

If a dose is missed, take it as soon as remembered unless it is almost time for the next dose. Do not double the dose to make up for a missed one. For cyclic regimens, contact a healthcare provider for guidance if a dose is missed to maintain proper sequencing.

Overdose

Symptoms may include nausea, vomiting, drowsiness, and dizziness. No specific antidote exists; provide symptomatic and supportive care. Dialysis is not effective due to high protein binding. In case of suspected overdose, contact poison control or seek emergency medical attention.

Storage

Store at 20°–25°C (68°–77°F); excursions permitted to 15°–30°C (59°–86°F). Keep in original blister packaging to protect from light and moisture. Keep out of reach of children and pets. Do not use after expiration date.

Disclaimer

This information is for educational purposes and does not replace professional medical advice. Always consult a healthcare provider for diagnosis, treatment decisions, and individualized dosage recommendations. Do not initiate or discontinue therapy without medical supervision.

Reviews

Clinical studies demonstrate Prometrium’s efficacy in reducing endometrial hyperplasia risk by up to 90% when used cyclically with estrogen. Patient reports often note improved sleep and reduced menopausal symptoms, though some report persistent drowsiness. Systematic reviews confirm its role as a well-tolerated option in HRT when appropriately prescribed.