BMA Concise Guide to Medicine & Drugs


Brand names Arret, Boots Diareze, Diocalm Ultra, Imodium

Used in the following combined preparation Diocalm Plus


Drug group Antidiarrhoeal drug

Overdose danger rating Medium

Dependence rating Low

Prescription needed No (most preparations)

Available as generic Yes


Loperamide is an antidiarrhoeal drug available in tablet, capsule, or liquid form. It reduces the loss of water and salts from the bowel and slows bowel activity, resulting in the passage of firmer bowel movements at less frequent intervals.

A fast-acting drug, loperamide is widely prescribed for both sudden and recurrent bouts of diarrhoea. However, it is not generally recommended for diarrhoea caused by infection because it may delay the expulsion of harmful substances from the bowel. Loperamide is often prescribed for people who have had a colostomy or an ileostomy, to reduce fluid loss from the stoma (outlet).

Adverse effects from this drug are rare, and there is no risk of abuse, as there may be with the opium-based antidiarrhoeals. It can be purchased over the counter in a pharmacy.


Follow instructions on the label. Call your doctor if symptoms worsen.

How taken/used Tablets, capsules, liquid.

Frequency and timing of doses Acute diarrhoea Take a double dose at start of treatment, then a single dose after each loose faeces, up to the maximum daily dose. Chronic diarrhoea 2 x daily.

Adult dosage range Acute diarrhoea 4mg (starting dose), then 2mg after each loose bowel movement (12–16mg daily); usual dose 6–8mg daily. Use for up to 5 days only (3 days only for children 4–8 years), then consult your doctor. Chronic diarrhoea 4–8mg daily (up to 16mg daily).

Onset of effect Within 1–2 hours.

Duration of action 6–18 hours.

Diet advice Ensure adequate fluid, sugar, and salt intake during a diarrhoeal illness.

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

Missed dose Do not take the missed dose. Take your next dose if needed.

Stopping the drug Can be safely stopped as soon as you no longer need it.

Exceeding the dose An occasional unintentional extra dose is unlikely to be a cause for concern. Large overdoses may cause constipation, vomiting, or drowsiness, and affect breathing. Notify your doctor.


Most adverse effects are rare with loperamide and some are difficult to distinguish from the effects of the diarrhoea it is used to treat. Headache is the most common adverse effect; consult your doctor if it is severe. If symptoms such as bloating, abdominal pain, or fever persist or worsen during treatment with loperamide, consult your doctor. If drowsiness, dizziness, or constipation occur, you should stop taking the drug. If your skin becomes itchy or you develop a rash, consult your doctor, and, with a rash, also stop taking the drug.




Be sure to consult your doctor or pharmacist before taking this drug if:

· You have long-term liver or kidney problems.

· You have had recent abdominal surgery.

· You have an infection or blockage in the intestine, pseudomembranous colitis, or ulcerative colitis.

· You are taking other medicines.

Pregnancy Safety in pregnancy not established. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk and may affect the baby. Discuss with your doctor.

Infants and children Not to be given to children under 4 years. Reduced dose necessary in older children. Children can be very sensitive to the effects of this drug so care should be taken.

Over 60 No special problems.

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

Alcohol No known problems.


Although this drug is not usually taken for prolonged periods (except by those with a medically diagnosed long-term gastrointestinal condition), special problems are not expected during long-term use.