How does this medication work? What will it do for me?

Misoprostol belongs to the class of medications called synthetic prostaglandins. This medication is used to treat and prevent stomach (gastric) and intestinal (duodenal) ulcers.

It is used to treat and prevent ulcers caused by a class of painkillers called nonsteroidal anti-inflammatory drugs (NSAIDs). It is also used to treat ulcers caused by peptic ulcer disease, which are most often caused by H. pylori (a bacteria that causes ulcers of the stomach and intestine).

Misoprostol is a synthetic prostaglandin that acts just like the natural prostaglandin found in your body. It works by decreasing acid and increasing mucus and blood flow to the stomach, which protects the walls of the stomach and intestine.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

100 µg
Each round, white, flat-faced, bevelled-edged tablet engraved "MISO" over "100" on one side contains 100 µg misoprostol. Nonmedicinal ingredients: microcrystalline cellulose, hydroxypropyl methylcellulose, croscarmellose sodium, and magnesium stearate.

200 µg
Each hexagonal, white, flat-faced, bevelled-edged tablet scored and engraved "MISO" over "200" on one side contains 200 µg misoprostol. Nonmedicinal ingredients: microcrystalline cellulose, hydroxypropyl methylcellulose, croscarmellose sodium, and magnesium stearate.

How should I use this medication?

The recommended adult dose of misoprostol ranges from 400 µg to 800 µg daily, taken in 2 to 4 equally divided doses (e.g., 100 µg 4 times daily, 200 µg twice daily, 200 µg 4 times daily).

Misoprostol should be taken with food or milk to reduce the risk of side effects, such as diarrhea. Also, to reduce the risk of diarrhea, avoid antacids that contain magnesium. Antacids containing aluminum (but not magnesium) may be used to relieve symptoms such as heartburn.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by the doctor. This medication may cause loose stools, diarrhea, and abdominal cramping while your body adjusts to it. These symptoms should go away within a few days. Do not stop the medication without first talking with your doctor.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Misoprostol should not be taken by anyone who:

  • is allergic to misoprostol or to any of the ingredients of the medication
  • is pregnant

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal or stomach pain (mild)
  • bleeding from the vagina
  • constipation
  • cramps in the lower abdomen or stomach area
  • diarrhea
  • gas
  • headache
  • heartburn, indigestion, or acid stomach
  • nausea or vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • abdominal pain
  • convulsions (seizures)
  • difficulty breathing
  • drowsiness
  • fast or pounding heartbeat
  • fever
  • low blood pressure
  • severe diarrhea
  • slow heartbeat
  • tremor

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Diarrhea: Rare instances of severe diarrhea leading to dehydration have been reported with use of this medication. People with an underlying condition such as irritable bowel disease or those for whom dehydration would be dangerous should be monitored closely by their doctor.

Epilepsy: Epileptic seizures have been reported with medications like misoprostol when administered by routes other than oral (by mouth). Therefore, misoprostol should be used by people with epilepsy only when their epilepsy is adequately controlled and the expected benefits outweigh the potential risks.

Pregnancy: Women who may become pregnant should use adequate birth control (e.g., birth control pills, condoms, or intrauterine devices) while taking misoprostol. Since misoprostol increases the risk of miscarriage, a woman who may be pregnant should not start taking misoprostol until she is sure that she is not pregnant. If you suspect you are pregnant, stop the medication and contact your doctor.

Breast-feeding: Breast-feeding mothers should not take misoprostol, as it may cause significant diarrhea for breast-feeding infants.

Children: The safety and effectiveness of this medication have not been established for children and adolescents under 18 years of age.

What other drugs could interact with this medication?

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.