Medroxyprogesterone acetate
progestins
Progestogens (progestins)Pregnancy: contraindicated
Not used in pregnancy and stopped if pregnancy occurs; studies have not found a higher rate of birth defects after exposure before or in early pregnancy.
A synthetic progestin: a contraceptive injection every three months, and tablets for bleeding disorders and to protect the uterus during estrogen therapy.
Also called: DMPA (depot medroxyprogesterone acetate)
Quick facts
- Group
- Progestogens (progestins)
- Target
- Progesterone receptor (PR), a nuclear receptor
- Used for
- Contraception · Pain of endometriosis
- Key effects
- Irregular bleeding or spotting · Weight gain
- Monitor
- Bone health with long-term injection use
- ATC
- G03DA02
No doses: the clinician sets them by the current guideline.
Mechanism of action
No structure with medroxyprogesterone acetate on the progesterone receptor is available; the figure shows progesterone itself in the ligand-binding domain of the human receptor, the same site the drug occupies.
Medroxyprogesterone acetate is a derivative of progesterone that activates the progesterone receptor. As a depot injection it suppresses gonadotropin secretion, so follicles do not mature and ovulation stops; it also thickens cervical mucus. As tablets it converts an estrogen-primed endometrium from proliferative to secretory, controls irregular bleeding and prevents hyperplasia during estrogen therapy. It has some androgenic and glucocorticoid activity and little estrogenic effect.
- Medroxyprogesterone binds the progesterone receptor
- At the pituitary it lowers LH and FSH, so ovulation stops
- In the endometrium the lining becomes secretory and stops proliferating
- Result: contraception, controlled bleeding, a protected endometrium
Indications
- Contraception (depot injection every three months)
- Pain of endometriosis (injection) Endometriosis →
- Abnormal uterine bleeding from hormonal imbalance (tablets) Abnormal uterine bleeding →
- Secondary amenorrhoea (tablets)
- Prevention of endometrial hyperplasia in postmenopausal women with a uterus taking estrogen (tablets) Endometrial hyperplasia →
Adverse effects
Common
- Irregular bleeding or spotting; later often amenorrhoea with the injection
- Weight gain
- Headache, dizziness, nervousness
- Breast tenderness
- Lower libido; injection-site reactions
Contraindications
- Pregnancy, known or suspected
- Undiagnosed vaginal bleeding
- Known or suspected breast cancer
- Active or past thromboembolism or cerebrovascular disease
- Significant liver disease
- Hypersensitivity to the drug
Key interactions
- CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John's wort)
- May reduce contraceptive effectiveness; a backup or other method is used
- CYP3A4 inhibitors
- Can raise levels of oral medroxyprogesterone
What is monitored
- Bone health with long-term injection use (calcium and vitamin D intake; bone density if needed)
- Bleeding pattern
- Weight and blood pressure
- Signs of thrombosis, visual or neurological symptoms
- Breast examination
Administration and safety
- The contraceptive injection is shaken vigorously and given deep intramuscularly (gluteal or deltoid) by staff; a subcutaneous product also exists and the two are not interchangeable
- The first injection is given only when pregnancy is unlikely, as the label times it (early in the cycle or after birth)
- Repeat injections are given on schedule; if late, pregnancy is ruled out first
- Tablets with estrogen are taken on the days the regimen specifies
Pregnancy and breastfeeding
Not used in pregnancy and stopped if pregnancy occurs; studies have not found a higher rate of birth defects after exposure before or in early pregnancy.
Nursing care
- Record the date of the next injection and remind the person
- Teach about irregular bleeding and later absence of periods
- Teach calcium and vitamin D intake; long use beyond about two years is reviewed
- Remind that it does not protect against HIV or other sexually transmitted infections
- Teach the warning signs of a clot: leg pain or swelling, chest pain, sudden breathlessness, sudden headache or vision change
Pharmacokinetics
- Absorption
- Tablets are absorbed quickly and food increases absorption; the injection forms a slowly released depot in muscle or under the skin
- Distribution
- Highly bound to albumin
- Metabolism
- Extensively in the liver, mainly by CYP3A4
Test yourself
Think of the answer, then tap the question to see it.
What is the boxed warning of the medroxyprogesterone contraceptive injection?
Loss of bone mineral density, which grows with duration of use and may not be completely reversible.
Why is a backup method needed when a DMPA user starts rifampicin?
Rifampicin induces CYP3A4 and may lower medroxyprogesterone levels and contraceptive effectiveness.
What is the role of oral medroxyprogesterone in menopausal hormone therapy?
It protects the endometrium of women with a uterus from estrogen-driven hyperplasia and cancer.
Connections
← Back to the class: Progestogens (progestins)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - MEDROXYPROGESTERONE ACETATE injection, suspension (DailyMed (U.S. National Library of Medicine), 2026); DailyMed - MEDROXYPROGESTERONE ACETATE tablet (DailyMed (U.S. National Library of Medicine), 2026); Medroxyprogesterone Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Medroxyprogesterone: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2017).
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Representative model, for educational purposes only.