Diphenoxylate with atropine (Lomotil) for short-term diarrhoea
Co-phenotrope
A combination medicine (diphenoxylate with atropine) used for short-term relief of diarrhoea.
What is Co-phenotrope?
Co-phenotrope, known by the brand name Lomotil, combines diphenoxylate with a small amount of atropine and is used for short-term relief of diarrhoea. Diphenoxylate is an opioid-related medicine that slows the bowel. The most important safety point is that it is dangerous in young children, who are very sensitive to its opioid effects, so it must be kept locked away out of reach. It can cause drowsiness, so do not drive if affected, and it should be used with care in diarrhoea caused by bowel infections, as slowing the bowel can be harmful; it is not for acute infective or inflammatory diarrhoea without medical advice.
Education and reference only. This is a plain-language guide to Co-phenotrope — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Co-phenotrope is a combination medicine used for the short-term relief of diarrhoea. It contains diphenoxylate, which is related to the opioid painkillers and slows down the movement of the bowel, together with a small amount of atropine, which is included partly to discourage misuse. It is best known by the brand name Lomotil. It is taken by mouth as tablets. Because diphenoxylate is opioid-related, it carries important safety cautions, especially around children, drowsiness and use in diarrhoea caused by infection.
How it works
The diphenoxylate in co-phenotrope acts on the bowel in a way similar to opioids, slowing down the muscle movements that push stool along. This gives the bowel more time to reabsorb water, so stools become firmer and less frequent, relieving diarrhoea. The atropine is added in a small amount to help discourage misuse and contributes some antimuscarinic effects. Because it slows the bowel, it can be harmful in certain types of diarrhoea, particularly some bowel infections and inflammatory bowel conditions, where keeping the bowel moving is actually important, which is why it is not suitable for every kind of diarrhoea.
Company & origin
Originated / developed by: Generic (long-established).
A combination antidiarrhoeal (diphenoxylate with atropine) used in the UK for short-term relief of diarrhoea.
Practical use
How to take Co-phenotrope
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth as directed for short-term relief of diarrhoea.
- Keep it locked away and well out of reach of children, as it is dangerous for them.
- Do not drive or use machinery if it makes you feel drowsy, and be careful with alcohol.
- Do not use it for diarrhoea with a high fever, blood in the stool or a suspected bowel infection without medical advice.
- Drink plenty of fluids and seek advice if diarrhoea is severe or does not settle.
Weighing it up
Advantages & disadvantages of Co-phenotrope
Advantages
- Provides effective short-term relief of diarrhoea by slowing the bowel.
- Taken by mouth as tablets.
- A long-established medicine with well-understood use.
Disadvantages
- Dangerous in young children, so it must be kept locked away out of reach.
- Can cause drowsiness, so it is not ideal before driving or with alcohol.
- Should be avoided or used with care in diarrhoea caused by bowel infections or inflammation.
Practical use
Good to know
The most important safety point about co-phenotrope is the danger to young children. Because diphenoxylate is opioid-related, even a small amount can seriously harm a child, so it must always be kept locked away and well out of reach, and an overdose is a medical emergency. It can cause drowsiness, so you should not drive or use machinery if affected, and it adds to the effects of alcohol and other sedating medicines. It should be used with care, or avoided, in diarrhoea caused by a bowel infection or in inflammatory bowel conditions, because slowing the bowel can make things worse; it is not for acute infective or colitis-type diarrhoea without medical advice. It is intended for short-term use, and you should seek advice if diarrhoea is severe, bloody, or does not settle.
Who should not take it / use with caution
- It must not be given to young children, who are very sensitive to its opioid effects.
- It should not be used in diarrhoea with a high fever, blood in the stool or a suspected serious bowel infection without medical advice.
- It should be avoided in active inflammatory bowel disease flares where slowing the bowel could be harmful.
- People who have had a serious allergic reaction to its ingredients should not use it.
Monitoring
- Checking that diarrhoea is settling and that it is being used only for the short term.
- Watching for excessive drowsiness, especially with other sedating medicines.
- Making sure it is stored safely away from children.
Side effects
- Drowsiness or dizziness.
- Dry mouth, blurred vision or constipation, partly from the atropine.
- Tummy discomfort, nausea or, if the bowel is slowed too much, bloating.
- In overdose, especially in children, dangerous slowing of breathing, which is a medical emergency.
Key interactions
- Alcohol and other sedating medicines add to its drowsiness.
- Other opioids and antimuscarinic medicines can add to its effects.
- It should not be combined with certain antidepressants called MAOIs without advice.
Available as: Tablets taken by mouth.
Answers
Co-phenotrope: frequently asked questions
What is co-phenotrope used for?
It is used for the short-term relief of diarrhoea, combining diphenoxylate, which slows the bowel, with a small amount of atropine.
Why is it dangerous for children?
Diphenoxylate is opioid-related, and children are very sensitive to it, so even a small amount can cause serious harm; it must be kept locked away.
Can I drive while taking it?
It can cause drowsiness, so you should not drive or use machinery if you feel affected, and you should be careful with alcohol.
Can I use it for any diarrhoea?
No. It should be avoided or used with care in diarrhoea caused by a bowel infection or inflammation, where slowing the bowel can be harmful.
Is it the same as Lomotil?
Yes, Lomotil is a well-known brand name for co-phenotrope, the combination of diphenoxylate with atropine.
The wider class
About Antidiarrhoeal (diphenoxylate with atropine)
Co-phenotrope belongs to the antidiarrhoeal (diphenoxylate with atropine) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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