[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/) › Progesterone

# Progesterone

## progestins?

Progestogens (progestins)

## Pregnancy: contraindicated?

The oral capsule is not used during pregnancy, according to its label.

The natural ovarian hormone, as oral capsules, used with estrogen to protect the uterus after menopause and to bring on a period in amenorrhoea.

Updated Nov 1, 2026

Also called: Micronised progesterone

## Quick facts

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

**Target**
Progesterone receptor (PR), a nuclear receptor

**Used for**
Prevention of endometrial hyperplasia

**Key effects**
Drowsiness and dizziness · Headache · Abdominal pain

**Monitor**
Abnormal vaginal bleeding · Blood pressure

**ATC**
G03DA04

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**Progesterone

ⓘ The figure shows progesterone itself in the ligand-binding domain of the human progesterone receptor.

**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

Therapeutic progesterone is chemically identical to the hormone of the corpus luteum. It activates the progesterone receptor in the endometrium, which changes the estrogen-primed lining from proliferative to secretory and limits its growth. Given for part of each cycle alongside estrogen, it prevents endometrial hyperplasia; stopping it after a course causes a withdrawal bleed in secondary amenorrhoea.

- Progesterone binds the progesterone receptor of the endometrium
- The estrogen-primed lining becomes secretory
- Endometrial growth is limited, preventing hyperplasia
- Stopping it after a course triggers a withdrawal bleed

## Indications

- Prevention of endometrial hyperplasia in postmenopausal women with a uterus taking estrogen [Endometrial hyperplasia →](https://durgical.com/en/conditions/endometrial-hyperplasia/)
- Part of menopausal hormone therapy with estrogen [Menopause and climacteric syndrome →](https://durgical.com/en/conditions/menopause-and-climacteric-syndrome/)
- Secondary amenorrhoea

## Adverse effects

### Common

- Drowsiness and dizziness
- Headache
- Breast tenderness
- Abdominal pain, bloating
- Mood changes, fatigue

### Serious (rare, important)

- Venous thromboembolism and stroke (in combined therapy with estrogen)
- Breast cancer and heart attack risk with estrogen plus progestin
- Probable dementia in women over 65 on combined therapy
- Visual loss from retinal thrombosis
- Severe allergy in people allergic to peanuts

## Contraindications

- Allergy to peanuts (the capsules contain peanut oil) or other ingredients
- Undiagnosed abnormal genital bleeding
- Known, suspected or past breast cancer
- Active or past venous thromboembolism, stroke or heart attack
- Liver disease
- Pregnancy, known or suspected

## Key interactions

**Ketoconazole and other CYP3A4 inhibitors**
Higher progesterone levels

**St John's wort**
May lower progesterone levels

## What is monitored

- Abnormal vaginal bleeding
- Blood pressure
- Breast examination and mammography as for any menopausal therapy
- Signs of thrombosis or visual change
- Drowsiness

## Administration and safety

- Oral capsule taken at bedtime, because it causes drowsiness and dizziness
- Taken on the cycle days the regimen sets, with estrogen
- With difficulty swallowing, taken with a full glass of water while standing
- Peanut allergy is asked about before the first dose

## Pregnancy and breastfeeding

The oral capsule is not used during pregnancy, according to its label.

## Nursing care

- Ask about peanut allergy before giving it
- Teach to take it at bedtime and to take care driving or using machines
- Teach to rise slowly to avoid fainting
- Teach warning signs: leg pain or swelling, chest pain, sudden breathlessness, weakness, vision change, breast lump
- Report any unexpected vaginal bleeding

## Pharmacokinetics

**Absorption**
Oral capsules; food increases absorption

**Distribution**
Very highly protein-bound

**Metabolism**
Mainly in the liver to pregnanediols and pregnanolones; CYP3A4 inhibitors raise its levels

**Elimination**
Conjugated metabolites, mostly in urine

**Onset and duration**
Peak levels within a few hours of a dose

## Memory aid

PROgesterone PROtects the uterus from estrogen: capsule at bedtime, no peanuts.

## Test yourself

Think of the answer, then tap the question to see it.

## Why are progesterone capsules taken at bedtime?

They can cause marked drowsiness and dizziness.

## Which food allergy contraindicates oral progesterone capsules?

Peanut allergy: the capsules contain peanut oil.

## What is the main purpose of progesterone in menopausal hormone therapy?

To protect the endometrium of a woman with a uterus from estrogen-driven hyperplasia.

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

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

## What the labels mean

**Pregnancy: contraindicated**
The oral capsule is not used during pregnancy, according to its label.

## Connections

## Related drugs 3

- [Medroxyprogesterone acetate](https://durgical.com/en/pharmacology/medroxyprogesterone-acetate/)
- [Estradiol](https://durgical.com/en/pharmacology/estradiol/)
- [Conjugated estrogens](https://durgical.com/en/pharmacology/conjugated-estrogens/)

## Related conditions 2

- [Endometrial hyperplasia](https://durgical.com/en/conditions/endometrial-hyperplasia/)
- [Menopause and climacteric syndrome](https://durgical.com/en/conditions/menopause-and-climacteric-syndrome/)

[← 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 - PROGESTERONE capsule](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7d73f08d-2de7-44b6-9e44-2d488fe02517) (DailyMed (U.S. National Library of Medicine), 2026); [Progesterone: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a604017.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=G03DA04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/progesterone/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/progesterone/