What is Meprate (medroxyprogesterone) tablet, its mechanism of action, and when to take it during the menstrual cycle for treating menstrual disorders?

Meprate (Medroxyprogesterone Acetate): Overview and Clinical Use

What is Meprate?

Meprate is a brand name for medroxyprogesterone acetate (MPA), a synthetic progestin hormone that mimics the action of natural progesterone in the body. 1 It is available in oral tablet form, typically in 5 mg or 10 mg strengths, and is distinct from the injectable contraceptive form (Depo-Provera). 1

Primary Clinical Uses

Meprate tablets are prescribed for three main indications:

• Treatment of secondary amenorrhea (absence of menstrual periods in women who previously menstruated normally) 1
• Management of abnormal uterine bleeding due to hormonal imbalance when no structural pathology is present 1
• Reduction of endometrial hyperplasia risk in postmenopausal women receiving estrogen replacement therapy 1

Additional off-label uses include treatment of endometriosis, where oral MPA at 30-50 mg daily has demonstrated effectiveness in relieving symptoms and improving disease staging. 2, 3

Mechanism of Action

Medroxyprogesterone acetate works by binding to progesterone receptors throughout the reproductive system, producing multiple physiological effects:

• Endometrial transformation: MPA converts estrogen-primed endometrium into a secretory state, then induces atrophic changes with prolonged use 1, 4
• Ovulation suppression: At higher doses, MPA inhibits the midcycle LH surge, preventing ovulation 2, 5
• Cervical mucus thickening: Creates a barrier to sperm penetration 5
• Anti-proliferative effects: Induces pseudodecidualized reaction and atrophic changes in both normal endometrium and ectopic endometrial tissue (in endometriosis) 2

The ultrastructural response shows initial endometrial maturation followed by inhibition and eventual atrophy. 4

When to Take During the Menstrual Cycle

For Secondary Amenorrhea (Absent Periods)

Therapy may be started at any time since there is no predictable cycle. 1 The standard regimen is:

• Dosage: 5-10 mg daily for 5-10 days (10 mg for 10 days is optimal for adequate secretory transformation) 1
• Expected outcome: Withdrawal bleeding typically occurs within 3-7 days after stopping the medication 1
• Critical prerequisite: Pregnancy must be ruled out before initiating treatment 6, 1

If no withdrawal bleeding occurs after completing the course, further evaluation is warranted for other causes of amenorrhea including thyroid dysfunction, hyperprolactinemia, or polycystic ovary syndrome. 6

For Abnormal Uterine Bleeding

Begin on the calculated 16th or 21st day of the menstrual cycle (counting from the first day of the last menstrual period). 1 The regimen is:

• Dosage: 5-10 mg daily for 5-10 days (10 mg for 10 days beginning on day 16 is suggested for optimal effect) 1
• Expected outcome: Withdrawal bleeding occurs within 3-7 days after discontinuation 1
• Planned menstrual cycling: Women with recurrent abnormal bleeding may benefit from scheduled cycles with MPA 1

For Endometrial Protection with Estrogen Therapy

Two timing options are available for postmenopausal women on estrogen:

• Sequential regimen: 5-10 mg daily for 12-14 consecutive days per month, starting either on day 1 or day 16 of the cycle 1
• Continuous regimen: Can be used with continuous estrogen therapy 1

Important Clinical Considerations

Absolute Contraindications

Do not prescribe Meprate if the patient has: 6, 1

• Active or history of arterial thromboembolic disease (stroke, myocardial infarction)
• Known or suspected breast cancer or history of breast cancer
• Active thrombophlebitis or thromboembolic disorders
• Known liver impairment or disease
• Undiagnosed vaginal bleeding
• Known hypersensitivity to medroxyprogesterone acetate
• Confirmed or suspected pregnancy

Pre-Treatment Requirements

Minimal testing is required before prescribing oral MPA: 6

• Blood pressure measurement is not required 6
• Pelvic examination is not required 6
• Laboratory tests (glucose, lipids, liver enzymes) are not necessary 6
• Clinical breast examination is not required 6

However, adequate diagnostic measures such as endometrial sampling should be undertaken when indicated to rule out malignancy in cases of undiagnosed persistent or recurring abnormal vaginal bleeding. 1

Key Counseling Points

Patients must understand the following:

• Start at the lowest effective dose and discuss with your healthcare provider whether the dose is working adequately 1
• Regular follow-up (every 3-6 months) is recommended to determine if continued treatment is necessary 1
• This is NOT a contraceptive method when used in the oral form for menstrual disorders—additional contraception is needed if pregnancy prevention is desired 6
• Hypertension is not a contraindication to oral medroxyprogesterone use 6

Common Pitfalls to Avoid

Do not confuse oral MPA (Meprate) with injectable DMPA (Depo-Provera):

• Injectable Depo-Provera is a long-acting contraceptive given every 13 weeks and should only be considered when long-term contraception (≥3 months) is the primary goal, not for menstrual cycle planning 7, 6
• Injectable DMPA causes delayed return to fertility (15-49 weeks), menstrual irregularities in nearly all patients initially, and potential weight gain 8, 7
• Oral MPA for menstrual disorders allows for brief cycle manipulation and does not have the prolonged effects of the injectable form 6

Drug Interactions

Certain medications can reduce MPA efficacy, including: 6

• Anticonvulsants (phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine)
• Rifampin or rifabutin
• Some antiretroviral medications

Patients taking these medications should inform their healthcare provider before starting MPA. 6