[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Progestogens (progestins)](https://durgical.com/en/pharmacology/classes/progestogens/) › Medroxyprogesterone acetate

# 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.

Updated Nov 1, 2026

Also called: DMPA (depot medroxyprogesterone acetate)

## Quick facts

**Group**
[Progestogens (progestins)](https://durgical.com/en/pharmacology/classes/progestogens/)

**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.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Progesterone receptor (PR), a nuclear receptor**Medroxyprogesterone acetate

ⓘ 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.

**Target in 3D:** Progesterone receptor (PR), a nuclear receptor. PDB structure 1A28 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1A28) · Drag to rotate · pinch to zoom

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 →](https://durgical.com/en/conditions/endometriosis/)
- Abnormal uterine bleeding from hormonal imbalance (tablets) [Abnormal uterine bleeding →](https://durgical.com/en/conditions/abnormal-uterine-bleeding/)
- Secondary amenorrhoea (tablets)
- Prevention of endometrial hyperplasia in postmenopausal women with a uterus taking estrogen (tablets) [Endometrial hyperplasia →](https://durgical.com/en/conditions/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

### Serious (rare, important)

- Loss of bone mineral density with the injection, greater with longer use and possibly not fully reversible
- Venous thromboembolism and stroke
- Breast cancer risk (with estrogen in menopausal therapy; slight increase in young recent users of the injection)
- Meningioma
- Delayed return of fertility after the injection; ectopic pregnancy if pregnancy occurs

## 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

## Memory aid

DMPA = «Depot Means Pause in Ovulation and Bone»: every three months, watch the bones.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/medroxyprogesterone-acetate/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**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.

## Connections

## Related drugs 4

- [Norethisterone](https://durgical.com/en/pharmacology/norethisterone/)
- [Progesterone](https://durgical.com/en/pharmacology/progesterone/)
- [Conjugated estrogens](https://durgical.com/en/pharmacology/conjugated-estrogens/)
- [Levonorgestrel](https://durgical.com/en/pharmacology/levonorgestrel/)

## Related conditions 3

- [Endometriosis](https://durgical.com/en/conditions/endometriosis/)
- [Abnormal uterine bleeding](https://durgical.com/en/conditions/abnormal-uterine-bleeding/)
- [Endometrial hyperplasia](https://durgical.com/en/conditions/endometrial-hyperplasia/)

[← Back to the class: Progestogens (progestins)](https://durgical.com/en/pharmacology/classes/progestogens/)

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](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6457d70a-2f25-4935-8511-726d988f7a03) (DailyMed (U.S. National Library of Medicine), 2026); [DailyMed - MEDROXYPROGESTERONE ACETATE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9eb200b0-db96-4a51-87ea-04db862978c8) (DailyMed (U.S. National Library of Medicine), 2026); [Medroxyprogesterone Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a604039.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [Medroxyprogesterone: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682470.html) (MedlinePlus (U.S. National Library of Medicine), 2017).

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Representative model, for educational purposes only.

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