[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Prostaglandin analogues (obstetric use)](https://durgical.com/en/pharmacology/classes/prostaglandin-analogues/) › Misoprostol

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# Misoprostol

Prostaglandin E1 analogue tablet that contracts the uterus and softens the cervix, and protects the stomach. Heat-stable; on the WHO essential list.

Updated 2026-11-01

- Class: [Prostaglandin analogues (obstetric use)](https://durgical.com/en/pharmacology/classes/prostaglandin-analogues/)
- Receptor: Prostaglandin E receptor EP3 (and other EP receptors)
- ATC code: G02AD06
- WHO Model List of Essential Medicines

◎**Prostaglandin E receptor EP3 (and other EP receptors)**Misoprostol

ⓘ Crystal structure of the human EP3 receptor with misoprostol free acid, the active form of misoprostol.

**Target in 3D:** Prostaglandin E receptor EP3 (and other EP receptors). PDB structure 6M9T (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6M9T) · Drag to rotate · pinch to zoom

## Mechanism of action

Misoprostol is converted to misoprostol acid, which binds prostaglandin E (EP) receptors. In the uterus it causes contractions and softens and opens the cervix; in the stomach it reduces acid secretion and strengthens mucosal defence. These actions explain its uses in obstetrics and in the prevention of ulcers caused by NSAIDs.

- Misoprostol is converted to the active misoprostol acid
- It binds EP receptors of the myometrium and cervix
- The uterus contracts and the cervix softens and opens
- In the stomach: less acid and more mucosal protection

## Pharmacokinetics

**Absorption**
Rapid by mouth (also given vaginally, buccally or sublingually); food lowers the peak

**Metabolism**
Quickly de-esterified to misoprostol acid, the active form

**Elimination**
Mostly in urine

**Half-life**
About 20–40 minutes (misoprostol acid)

**Onset and duration**
Peak levels about 12 minutes after an oral dose

## Indications

- Prevention and treatment of postpartum haemorrhage where oxytocin is not available or cannot be used safely [Postpartum haemorrhage →](https://durgical.com/en/conditions/postpartum-haemorrhage/)
- Management of incomplete miscarriage [Miscarriage (early pregnancy loss) →](https://durgical.com/en/conditions/miscarriage/)
- Medical abortion, together with mifepristone (WHO essential list)
- Induction of labour (low-dose vaginal tablet on the WHO list)
- Prevention of NSAID-induced gastric ulcers in high-risk patients [Peptic ulcer disease →](https://durgical.com/en/conditions/peptic-ulcer-disease/)

## Adverse effects

### Common

- Diarrhoea and abdominal pain (common, usually early and short-lived)
- Nausea, vomiting and flatulence
- Fever and shivering
- Headache

### Serious (rare, important)

- Uterine rupture, more likely late in pregnancy and with a previous caesarean or uterine scar
- Incomplete abortion and heavy bleeding
- Birth defects if the pregnancy continues after exposure
- Uterine hyperstimulation

## Contraindications

- Pregnancy when used to prevent NSAID ulcers
- Allergy to prostaglandins

## Key interactions

**Oxytocin and other oxytocic drugs**
Misoprostol augments their effect; oxytocin is not started within 4 hours of misoprostol

**Antacids containing magnesium**
Worse diarrhoea

## What is monitored

- Contractions, fetal heart rate and cervical change when used for induction
- Blood loss and uterine tone after birth
- Temperature (fever and shivering are common) and hydration if diarrhoea
- Confirmation that the uterus is empty after use for miscarriage

## Administration and safety

- Tablets are heat-stable and need no cold chain, which makes misoprostol useful in rural and low-resource settings.
- Route varies with the indication (oral, buccal, sublingual, vaginal); the route and timing come from the protocol in use.
- A previous caesarean or other uterine scar raises the risk of rupture; this is checked before use.
- Do not give oxytocin within 4 hours of misoprostol.

## Nursing care

- Before use for induction: check for a uterine scar, fetal heart rate and contractions.
- During induction: monitor contractions and the fetal heart rate; report hyperstimulation.
- After birth or miscarriage: check uterine tone, bleeding, temperature and pain.
- Teaching: shivering, fever and diarrhoea are expected; heavy bleeding, severe pain or persistent fever need prompt review.
- In ulcer prevention: confirm the patient is not pregnant and explain that the medicine can cause abortion.

## Pregnancy and breastfeeding

It causes uterine contractions: it can cause abortion, birth defects and uterine rupture, so it is not used in pregnancy for ulcer prevention.

## Memory aid

Misoprostol: «the heat-proof tablet»: it opens the cervix, contracts the uterus and guards the stomach, and its price is diarrhoea, fever and shivering.

## Test yourself

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

## Why is misoprostol useful for postpartum haemorrhage in rural settings?

It is a heat-stable tablet that needs no cold chain or injection; WHO lists it when oxytocin is not available or cannot be used safely.

## What is the active form of misoprostol?

Misoprostol acid, formed quickly by de-esterification.

## Which uterine scar increases the risk of rupture with misoprostol?

A previous caesarean section or other uterine surgery.

## Which two non-obstetric effects explain misoprostol's use with NSAIDs?

Less gastric acid secretion and stronger mucosal protection.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/misoprostol/)

## Related drugs

- [Mifepristone](https://durgical.com/en/pharmacology/mifepristone/)
- [Oxytocin](https://durgical.com/en/pharmacology/oxytocin/)
- [Carboprost](https://durgical.com/en/pharmacology/carboprost/)

## Related conditions

- [Postpartum haemorrhage](https://durgical.com/en/conditions/postpartum-haemorrhage/)
- [Miscarriage (early pregnancy loss)](https://durgical.com/en/conditions/miscarriage/)
- [Peptic ulcer disease](https://durgical.com/en/conditions/peptic-ulcer-disease/)

[← Back to the class: Prostaglandin analogues (obstetric use)](https://durgical.com/en/pharmacology/classes/prostaglandin-analogues/)

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 - MISOPROSTOL tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a46d05a2-5014-40ff-8f1b-9eca1b0aff3a) (DailyMed (U.S. National Library of Medicine), 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/medicines/240) (World Health Organization, 2025); [Global health agencies issue new recommendations to help end deaths from postpartum haemorrhage](https://www.who.int/news/item/05-10-2025-global-health-agencies-issue-new-recommendations-to-help-end-deaths-from-postpartum-haemorrhage) (World Health Organization, 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=G02AD) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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