Misoprostol
A prostaglandin E1 analogue that prevents NSAID stomach ulcers and, in obstetrics, induces labor, treats bleeding after birth and ends pregnancy.
Drug card
- How it works
- Activating prostaglandin receptors in the uterus, stomach or eye
- Used for
- Preventing NSAID-induced stomach ulcers
- Inducing labor at term
- Preventing and treating bleeding after birth
- Medical abortion, with mifepristone or alone
- Known for
- Diarrhea
- Miscarriage or birth defects if a pregnancy continues
- Its name
- -prost- means a prostaglandin or analogue
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does misoprostol work?
Misoprostol is a prodrug, quickly de-esterified to misoprostol acid, a synthetic analogue of prostaglandin E1 (alprostadil). In the stomach it cuts acid secretion by parietal cells and raises mucus and bicarbonate. In the uterus it contracts the myometrium and relaxes and softens the cervix, which helps empty the uterus.
Uses
What is misoprostol used for?
- Preventing NSAID-induced stomach ulcers
- Inducing labor at term
- Preventing and treating bleeding after birth
- Medical abortion, with mifepristone or alone
- Incomplete or missed miscarriage
Side effects
Side effects of misoprostol
- DiarrheaKnown for
- Miscarriage or birth defects if a pregnancy continuesKnown forSerious
- Abdominal pain
- Nausea
- Vomiting
- Wind and bloating
- Headache
- Shivering and fever
- Uterine cramps and prolonged bleeding after abortion
- Overstrong or too frequent contractionsSerious
- Uterine ruptureSerious
- Heart attack or coronary spasm (rare)Serious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- For ulcer prevention, exclude pregnancy first and make sure reliable contraception is used.
- Not for labor induction after a cesarean or major uterine surgery: risk of uterine rupture.
- Taking it with food and avoiding magnesium antacids lessens diarrhea.
- Use with care in heart disease: heart attack, coronary spasm and severe hypotension have occurred.
Good to know: In the US it is licensed only for NSAID ulcers; WHO guidance backs its obstetric uses, where being heat-stable it works without a cold chain.
Remember it
A way to remember it
Prostaglandin E1 protects the stomach but empties the uterus.
Misoprostol shields the stomach lining from NSAID damage, yet the same drug contracts the pregnant uterus, so it is never used for ulcer prevention in pregnancy.
Written for biofideX
Its name
-prost- means prostaglandin or analogue
Misoprostol (a PGE1 analogue), alprostadil, epoprostenol and latanoprost share it. It can sit inside the name or end it.
- Every drug name stem
Its class
Prostaglandin analogues
Prostaglandin analogues are stable synthetic forms of prostaglandin E1, E2 or F2-alpha that activate prostaglandin receptors on smooth muscle and other cells. In the pregnant uterus they soften and open the cervix and make the myometrium contract; in the stomach misoprostol cuts acid and boosts mucus and bicarbonate; in the eye latanoprost increases fluid outflow, lowering pressure.
Easily mixed up with oxytocin and its analogues and proton pump inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Misoprostol tablets (Pfizer): label (DailyMed)
- Misoprostol tablets: label (DailyMed)
- Misoprostol 200 µg tablets: WHO-recommended summary of product characteristics (WHO Prequalification)
- Mifepristone tablets 200 mg: label (DailyMed)
- WHO updates guidance to help healthcare workers prevent postpartum haemorrhage (WHO)
- Misoprostol (NCI Thesaurus)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Reproductive and urinary health
Misoprostol is one of 9 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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