Misoprostol is a medication used to start labor, cause an abortion, prevent and treat stomach ulcers, and treat postpartum bleeding due to poor contraction of the uterus. For abortions it is often used with mifepristone or methotrexate. By itself effectiveness for this purpose is between 66% and 90%.

Molecular Structure


Class of Drug

Prostaglandin analogue, gastric mucosal protectant.

Mechanism of Action

Enhances gastric mucosal blood flow. Increases mucus and bicarbonate production. Decreases basal and stimulated gastric acid secretion.

Indications / Dosage / Route

Routes of Administration: Oral only.

Condition: Prevention of NSAID-induced gastric and duodenal ulcer

Dose: Adults: 200 μg q.i.d. Reduce to 100 μg q.i.d. if intolerance to side effects develops.

Adjustment of Dosage

Kidney disease: Adjust dosage according to side effects only.

Liver disease: Adjust dosage according to side effects only.

Elderly: None

Pediatric: Safety has not be established in children <18 years.

Onset of ActionDuration
30 min3-6 h

Food and Drug Interactions

Food: Misoprostol should be administered with meals and at bedtime.

Pregnancy: Category X.

Lactation: No data available. Potentially toxic to infant. Avoid breastfeeding.

Contraindications: Pregnancy, hypersensitivity to misoprostol.

Warnings / Precautions

> Misoprostol should not be prescribed for a female patient who is potentially capable of childbearing unless patient understands effect of misoprostol in causing abortion, is capable of complying with recommended contraception, and has a negative pregnancy test within 2 weeks of initiating therapy.

> To initiate misoprostol use in women of childbearing age, ideally begin on the second or third day of the next menstrual period following a negative pregnancy test in the prior 2 weeks.

Clinically Important Drug Interactions

> None.

Adverse Reactions

> Common: diarrhea, nausea, abdominal pain, headache, body aches, anxiety, arthralgia.

> Serious: miscarriage, anaphylaxis.

Parameters to Monitor

> Signs of diarrhea. This tends to be self limited and can be minimized by giving the drug with meals.

Advice to Patient

> Use two forms of birth control including hormonal and barrier methods.

Further Useful Info

> Usage of misoprostol to prevent NSAID-induced ulcers will probably decline with development of the COX-2 inhibitors, a new class of antiinflammatory agents (see celecoxib, rofecoxib).

> Off-label use includes treatment of refractory constipation.

> Misoprostol is also available on the market in a combination preparation with diclofenac (Arthrotec).

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