What is the recommended dosing regimen for medroxyprogesterone acetate (Med Roxy) for endometrial protection, treatment of abnormal uterine bleeding, and post‑menopausal hormone therapy?

Medroxyprogesterone Acetate Dosing Recommendations

For abnormal uterine bleeding due to ovulatory dysfunction, medroxyprogesterone acetate (MPA) should be dosed at 5-10 mg daily for 5-10 days, with the 10-day regimen administered from days 16-25 of the menstrual cycle providing superior cycle regulation and bleeding control compared to longer protocols. 1, 2

Dosing by Clinical Indication

Abnormal Uterine Bleeding (Ovulatory Dysfunction)

• Standard regimen: 5-10 mg daily for 5-10 days 1
• Optimal timing: Days 16-25 of menstrual cycle (10-day protocol) 1, 2
• Alternative timing: Days 11-25 (15-day protocol) - less effective 2
• The 10-day protocol (days 16-25) achieves better menstrual cycle regulation and more frequent cessation of bleeding, typically within 3 treatment cycles 2

Secondary Amenorrhea

• Dose: 5-10 mg daily for 5-10 days 1
• Optimal dose: 10 mg daily for 10 days provides optimal secretory endometrial transformation 1
• Therapy may be started at any time
• Withdrawal bleeding typically occurs 3-7 days after discontinuation 1

Endometrial Protection in Postmenopausal Hormone Therapy

• Sequential regimen: 5-10 mg daily for 12-14 consecutive days per month 1
• Can begin on day 1 or day 16 of cycle 1
• When combined with transdermal estradiol: 10 mg daily for 12-14 days every 28 days 3

Important note: Micronized progesterone (200 mg daily) is preferred over MPA when available due to superior cardiovascular and thrombotic safety profiles, though MPA remains a validated second choice 3

Continuous Combined Regimen (Postmenopausal)

• Dose: Minimum 2.5 mg daily 3
• Used to avoid withdrawal bleeding
• Provides endometrial protection when combined with estrogen 4

Acute Abnormal Uterine Bleeding (Outpatient Management)

For hemodynamically stable patients requiring urgent control:

• Loading protocol: Depot medroxyprogesterone acetate 150 mg IM injection PLUS oral MPA 20 mg every 8 hours for 3 days (9 doses total) 5
• Mean time to bleeding cessation: 2.6 days 5
• 100% efficacy in stopping bleeding within 5 days 5

Key Clinical Considerations

Treatment Duration and Monitoring

• Start at lowest effective dose 1
• Re-evaluate every 3-6 months 1
• For recurrent abnormal bleeding: planned menstrual cycling with MPA may be beneficial 1

When to Investigate Further

Before initiating MPA, rule out:

• Pregnancy (always test) 1
• Endometrial pathology (sampling indicated for persistent/recurrent bleeding) 1
• Structural lesions via ultrasound 6

Critical threshold: If endometrial thickness >4 mm on ultrasound in postmenopausal women with bleeding on HRT, hysteroscopy and histology are mandatory 6

Contraindications (Do Not Use)

• Undiagnosed vaginal bleeding 1
• Current or history of breast cancer or hormone-sensitive malignancies 1
• Active thromboembolic disease 1
• Liver disease 1
• Pregnancy 1

Common Pitfalls to Avoid

1. Don't use MPA as a pregnancy test - always confirm non-pregnant status first 1
2. Don't continue indefinitely without reassessment - the 3-6 month evaluation is essential 1
3. Don't ignore persistent bleeding - this requires endometrial evaluation regardless of treatment 1, 6
4. Don't use in women with cardiovascular risk factors without considering alternatives - micronized progesterone has better safety profile 3

Expected Outcomes

• Withdrawal bleeding: Occurs 3-7 days after stopping sequential therapy 1
• Amenorrhea rates (continuous combined): 76-81% by 6 months, 90-94% by 24 months 4
• Patient satisfaction: 57% overall, higher in women ≥35 years and those desiring uterine conservation 7

Special Populations

In young women with premature ovarian insufficiency requiring hormone replacement, MPA is a second-line progestin choice after micronized progesterone, given at 10 mg daily for 12-14 days per month when using sequential regimens, or 2.5 mg daily for continuous regimens 3