BMA Concise Guide to Medicine & Drugs

Misoprostol

Brand name Cytotec

Used in the following combined preparations Arthrotec, Napratec

QUICK REFERENCE

Drug group Anti-ulcer drug

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Misoprostol reduces acid secretion in the stomach and promotes the healing of gastric and duodenal ulcers. These types of ulcers may be caused by aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) which block the synthesis of naturally occurring chemicals called prostaglandins. Misoprostol is a synthetic prostaglandin that acts as a substitute for some of the natural prostaglandins and prevents ulcers from forming as well as promoting ulcer healing. Treatment with misoprostol usually causes the healing of ulcers in a few weeks. In some cases, misoprostol is given during treatment with aspirin or NSAIDs as a preventive measure, and combined preparations are available that reduce the likelihood of ulcers occurring. The most common adverse effects of misoprostol are diarrhoea and indigestion; if they are severe, it may be necessary to stop taking the drug. Diarrhoea can also be made worse by antacids containing magnesium, which should therefore be avoided.

Misoprostol also causes the uterus to contract. This may cause premature labour and so the drug must not be used during pregnancy. However, because of this effect, misoprostol may be used in medical terminations of pregnancy. The information here relates only to the anti-ulcer use of the drug.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets.

Frequency and timing of doses 2–4 x daily, with or after food.

Adult dosage range 400–800mcg daily.

Onset of effect Within 24 hours.

Duration of action Up to 24 hours; some effects may be longer lasting.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. If your next dose is due within 3 hours, take a single dose now and skip the next.

Stopping the drug Do not stop the drug without consulting your doctor; symptoms may recur.

Exceeding the dose An occasional unintentional extra dose is unlikely to be a cause for concern. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.

POSSIBLE ADVERSE EFFECTS

The most common side effects of misoprostol are diarrhoea and indigestion. These may be reduced by spreading the doses out during the day. Taking the drug with food may be recommended. If diarrhoea or indigestion are severe, or if you experience severe nausea and vomiting, discuss with your doctor as it may be necessary to stop the drug. More rarely, misoprostol may cause vaginal or intermenstrual bleeding, abdominal pain, dizziness, and a rash. If any of these occur, consult your doctor; you should also stop taking the drug if you develop a rash.

INTERACTIONS

Magnesium-containing antacids These may increase the severity of any diarrhoea caused by misoprostol.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You are, or are intending to become, pregnant.

· You have had a stroke.

· You have heart problems.

· You have high blood pressure.

· You have bowel problems.

· You are taking other medicines.

Pregnancy Misoprostol should not be taken by women of childbearing years. In exceptional cases, it may be prescribed on the condition that effective contraception is used. If taken during pregnancy, the drug can cause the uterus to contract before the baby is due.

Breast-feeding Safety not established. Discuss with your doctor.

Infants and children Not recommended.

Over 60 No special problems.

Driving and hazardous work Avoid such activities until you have learned how misoprostol affects you because the drug can cause dizziness.

Alcohol No problems expected, but excessive amounts may undermine the desired effect of the drug.

PROLONGED USE

No problems expected.