DIPHENOXYLATE
Brand names None
Used in the following combined preparations Diarphen, Lomotil, Tropergen.
Diphenoxylate is an antidiarrhoeal drug that is chemically related to the opiate analgesics. It reduces bowel contractions and, therefore, the fluidity and frequency of bowel movements. Available in tablet and liquid form, it is prescribed for the relief of sudden or recurrent bouts of diarrhoea.
The drug is not suitable for diarrhoea that is caused by infection, poisons, or antibiotics as it may delay recovery by slowing expulsion of harmful substances from the bowel. Diphenoxylate can cause toxic megacolon, 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. To guard against addiction, atropine is added to diphenoxylate tablets. If these are taken in excessive amounts, the atropine will cause highly unpleasant anticholinergic reactions. Diphenoxylate is especially dangerous for young children; be sure to store the drug out of their reach.
INFORMATION FOR USERS
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets, liquid.
Frequency and timing of doses
3-4 x daily.
Dosage range
Adults 10mg initially, followed by doses of 5mg.
Children Reduced dose necessary according to age and weight.
Onset of effect
Within 1 hour. Control of diarrhoea may take some hours.
Duration of action
Up to 24 hours.
Diet advice
Ensure adequate fluid intake during an attack of diarrhoea.
Storage
Keep in a closed container in a cool, dry place 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.
POSSIBLE ADVERSE EFFECTS
Side effects occur infrequently with diphenoxylate. If abdominal pain or
distension, nausea, or vomiting occur, notify your doctor.
INTERACTIONS
Sedatives
All drugs that have a sedative effect on the central nervous system may increase the sedative effect of diphenoxylate.
Monoamine oxidase inhibitors (MAOIs)
There is a risk of a dangerous rise in blood pressure if MAOIs are taken together with diphenoxylate.
QUICK REFERENCE
Drug group Opioid antidiarrhoeal drug
Overdose danger rating Medium
Dependence rating Medium
Prescription needed Yes
Available as generic No
SPECIAL PRECAUTIONS
Be sure to tell your doctor if:
You have a long-term liver problem.
You have severe abdominal pain.
You have bloodstained diarrhoea.
You have recently taken antibiotics.
You have ulcerative colitis.
You are taking other medications.
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 diphenoxylate affects you because the drug may cause drowsiness and dizziness.
Alcohol
Avoid. Alcohol may increase the sedative effects of this drug.
PROLONGED USE
Not usually recommended.
