BMA Concise Guide to Medicine & Drugs


Brand name Lomotil

Used in the following combined preparations None


Drug group Opioid antidiarrhoeal

Overdose danger rating Medium

Dependence rating Medium

Prescription needed Yes

Available as generic Yes


Co-phenotrope is an antidiarrhoeal drug that contains diphenoxylate and atropine. It reduces bowel contractions and the fluidity and frequency of bowel movements. It is used to relieve sudden or recurrent bouts of diarrhoea. It may also be used to control consistency of faeces following colostomy or ileostomy.

Co-phenotrope is not suitable for treating diarrhoea caused by infections, poisons, or antibiotics as it may delay recovery by slowing expulsion of harmful substances from the bowel. The drug can cause toxic megacolon which is a dangerous dilation of the bowel that shuts off the blood supply to the wall of the bowel and increases the risk of perforation.

At recommended doses, serious adverse effects are rare. However, if taken in excessive amounts, the atropine will cause highly unpleasant anticholinergic effects. This drug is especially dangerous for young children and should be stored out of their reach.


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 3–4 x daily.

Dosage range Adults 4 tablets (equivalent to 10mg diphenoxylate) initially, followed by 2 tablets (5mg) every 6 hours until diarrhoea is controlled. Children Reduced dose necessary according to age (not recommended under 4 years).

Onset of effect Within 1 hour. Control of diarrhoea may take some hours.

Duration of action 3–4 hours (single dose).

Diet advice Always drink plenty of water during an attack of diarrhoea.

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

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

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. Large overdoses may cause unusual drowsiness, dryness of the mouth and skin, restlessness, and in extreme cases, loss of consciousness. Symptoms of overdose may be delayed. Notify your doctor.


Drowsiness is the most common adverse effect of co-phenotrope. Other adverse effects, such as restlessness, headache, rash, itching, and dizziness, are infrequent. If it becomes difficult to pass urine, stop taking the drug and consult your doctor. If nausea, vomiting, or abdominal pain or distension occur, stop taking the drug and consult your doctor promptly.


Sedatives All drugs that have a sedative effect on the central nervous system may increase co-phenotrope’s sedative effect. They include anti-anxiety and sleeping drugs, antihistamines, opioid analgesics, antidepressants, and antipsychotics.

Monoamine oxidase inhibitors (MAOIs) There is a risk of a dangerous rise in blood pressure if MAOIs are taken together with co-phenotrope.


Be sure to tell your doctor if:

· You have long-term liver or kidney problems.

· You have severe abdominal pain.

· You have bloodstained diarrhoea.

· You have recently taken antibiotics.

· You have ulcerative colitis.

· You have prostate problems.

· You have recently travelled abroad.

· 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 cause drowsiness in the baby. Discuss with your doctor.

Infants and children Not recommended under 4 years. Reduced dose necessary for older children.

Over 60 Reduced dose may be necessary.

Driving and hazardous work Avoid such activities until you have learned how co-phenotrope affects you because the drug may cause drowsiness and dizziness.

Alcohol Avoid. Alcohol may increase the sedative effects of this drug.


Not usually recommended.