Medroxyprogesterone 17-acetate丨CAS 71-58-9

Chemical Overview

Medroxyprogesterone 17-acetate丨CAS 71-58-9 (MPA) is a synthetic progestin, a derivative of the natural hormone progesterone. It has enhanced potency and bioavailability due to its acetylation at the 17-alpha position. MPA is one of the most widely used progestins in medicine.

Applications of Medroxyprogesterone Acetate

1. Hormonal Contraceptives

MPA is a key active ingredient in:

Injectable contraceptives such as Depo-Provera, which provides long-term (3-month) birth control through intramuscular or subcutaneous injection.

Oral contraceptives, often in combination with estrogens for cycle regulation.

Its contraceptive action is due to:

Inhibition of ovulation by suppressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

Thickening of cervical mucus, making sperm penetration more difficult.

Thinning of the endometrium, reducing the likelihood of implantation.

2. Hormone Replacement Therapy (HRT)

Used in postmenopausal women to protect the endometrium from the hyperplastic effects of estrogen during HRT.

Combined with estradiol in many HRT formulations to reduce the risk of endometrial cancer.

3. Treatment of Menstrual Disorders

Medroxyprogesterone 17-acetate丨CAS 71-58-9 is used in:

Dysfunctional uterine bleeding

Amenorrhea (absence of menstruation)

Menorrhagia (heavy menstrual bleeding)
By mimicking natural progesterone, MPA helps regulate the menstrual cycle and promote normal withdrawal bleeding.

4. Management of Endometriosis and Fibroids

MPA helps suppress the growth of endometrial tissue and uterine fibroids by reducing estrogen stimulation through negative feedback mechanisms.

5. Cancer Therapy

In certain hormone-sensitive cancers, MPA is used for its anti-estrogenic effects:

Endometrial carcinoma

Renal cell carcinoma

Breast cancer (in select cases, particularly in postmenopausal women who are not candidates for standard therapy)

6. Appetite Stimulation in Cachexia

In patients with cancer, AIDS, or severe chronic illness:

MPA is sometimes prescribed off-label to increase appetite and promote weight gain.

It acts on glucocorticoid receptors and central pathways affecting hunger and metabolism.

7. Suppression of Gonadotropin Release

MPA is used for chemical castration or hormonal suppression in:

Sex offenders (in some countries, as part of legal or therapeutic programs)

Precocious puberty

Gender-affirming hormone therapy (as part of androgen suppression regimens)

Benefits of Medroxyprogesterone Acetate

1. Long-Acting and Convenient

The injectable form provides up to 12 weeks of contraception with a single dose.

Useful for individuals who prefer not to take daily pills or use barrier methods.

2. High Efficacy

When used properly, MPA provides over 99% effectiveness in preventing pregnancy.

Reliable, with a well-understood pharmacokinetic and safety profile.

3. Versatility

MPA serves multiple roles: contraceptive, hormone therapy agent, cancer treatment, and more.

Available in oral, injectable, and occasionally implantable forms.

4. Reduced Estrogen Exposure Risks

Can be used without estrogen in women with contraindications (e.g., history of thrombosis or breast cancer survivors).

Helps prevent endometrial hyperplasia during unopposed estrogen therapy.

5. Well-Documented Safety Record

Extensive clinical experience with millions of patients worldwide.

Approved by regulatory agencies globally, including the FDA and WHO for use in family planning.

6. Cost-Effective

Generic formulations are widely available.

Offers affordable and accessible hormonal management in both high- and low-income healthcare settings.

7. Potential Non-Contraceptive Health Benefits

May reduce the risk of:

Endometrial cancer

Ovarian cysts

Pelvic inflammatory disease (PID)

Also associated with reduced menstrual pain and lighter periods over time.

Conclusion

Medroxyprogesterone 17-acetate丨CAS 71-58-9 is a potent and highly versatile synthetic progestin with extensive clinical applications ranging from long-term contraception to hormone replacement therapy, menstrual regulation, and oncology. Its long-acting profile, proven efficacy, and broad therapeutic uses make it one of the most important compounds in reproductive and hormonal medicine. As healthcare needs evolve, MPA continues to play a key role in ensuring reproductive autonomy, hormonal balance, and supportive care in complex medical conditions.