Medroxyprogesterone Acetate Dose in Progesterone Challenge Test
The standard dose of medroxyprogesterone acetate (MPA) for a progesterone challenge test is 10 mg daily for 5-10 days, with most protocols using 10 mg daily for 10 days.
Standard Dosing Protocol
The progesterone challenge test uses 10 mg of oral medroxyprogesterone acetate daily for 10 days to assess estrogen status and endometrial responsiveness in women with amenorrhea. This dose is sufficient to induce withdrawal bleeding in women with adequate endogenous estrogen production and a functional outflow tract.
Pharmacologic Rationale
- MPA reaches peak plasma levels within 1-3 hours after oral administration, indicating rapid gastrointestinal absorption 1
- Plasma levels remain constant throughout treatment when administered daily, providing consistent progestational effect 1
- The 10 mg daily dose reliably inhibits ovulation and provides adequate progestational transformation of the endometrium 1
Clinical Interpretation
After completing the 10-day course:
- Withdrawal bleeding within 2-7 days indicates adequate estrogen priming of the endometrium and patent outflow tract
- No bleeding suggests either inadequate estrogen levels (hypoestrogenic state) or anatomic outflow obstruction
- The test helps differentiate anovulation from other causes of amenorrhea by confirming the presence of endogenous estrogen
Important Caveats
- Lower doses (5 mg daily) are insufficient to reliably inhibit ovulation in all women and may not provide adequate progestational effect for diagnostic purposes 1
- The 10 mg dose for 10 days provides consistent endometrial transformation without the risks associated with higher therapeutic doses used for other indications 1
- This diagnostic dose is distinct from therapeutic regimens: fertility-sparing therapy for endometrial cancer uses 400-600 mg/day 2, while appetite stimulation in cachexia uses 300-1200 mg/day 2