Co-phenotrope (Lomotil)

How does it work?

Lomotil tablets contain two active ingredients, diphenoxylate hydrochloride and atropine sulphate. This combination of medicines is known as co-phenotrope. (NB. Co-phenotrope tablets are also available without a brand name, ie as the generic medicine.) Both components of co-phenotrope help to slow down the activity of the bowel.

Diphenoxylate blocks nerve signals to intestinal muscles. This relaxes the muscles, reducing the amount of activity. This slows the passage of food through the gut. More water is absorbed from the food residue and the fluidity of faeces and the frequency of bowel movements are reduced. Diphenoxylate also eases painful muscle contractions and prevents spasm in the bowel.

Atropine sulphate blocks muscarinic receptors in the bowel. Nerve signals to the muscles in the bowel are blocked as a result of which the bowel muscles relax, preventing painful muscle spasm.

What is it used for?

  • Treatment of diarrhoea, together with rehydration therapy.
  • Relieve the symptoms of chronic and mild ulcerative colitis.
  • After colostomy or ileostomy, to help regulate stool formation.


  • Don't take this medicine and consult a doctor if any of the following apply to you: if your diarrhoea started either during or after taking a course of antibiotics, if the diarrhoea contains yellow or greenish mucus or blood, or if you also have a fever.
  • Acute diarrhoea makes you lose more fluids and salt than you usually would and can make you dehydrated. This medicine only treats the symtoms of diarrhoea and so will not rehydrate you. You should ensure that you drink plenty of fluids, and you may also want to take an oral rehydration therapy, which is a soluble powder containing sugars and salts, to help rehydrate you. This is particularly important for frail and elderly people. Rehydration salts can be bought from pharmacies.
  • This medicine may cause drowsiness. If affected do not drive or operate machinery. Alcohol should be avoided.
  • Do not exceed the recommended dose of this medicine, which will be stated in the product packaging or information leaflet supplied with the medicine.

Use with caution in

  • Decreased kidney function.
  • Decreased liver function.
  • Down's syndrome.
  • Pregnancy.
  • Breastfeeding.

Not to be used in

  • Children under the age of 16 years.
  • Conditions where preventing gut movement should be avoided, such as constipation, obstruction of the intestines (ileus) or when abdominal swelling (distension) develops.
  • Paralysis or inactivity in the intestines that prevents material moving through the gut (paralytic ileus).
  • Diarrhoea associated with acute attacks of ulcerative colitis.
  • Diarrhoea cause by infection of the gut with bacteria such as Salmonella, Shigella or Campylobacter.
  • Diarrhoea caused by inflammation of the gut as a result of antibiotic treatment (antibiotic-associated pseudomembranous colitis).
  • People with a head injury.
  • People with raised pressure inside the skull (intracranial pressure).
  • Jaundice.

This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • The safety of this medicine for use during pregnancy and breastfeeding has not been established. If you are pregnant or breastfeeding you should seek medical advice from your doctor before taking this medicine. It should only be used with caution, and only if the expected benefit to the mother outweighs any potential risk to the infant.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Nausea and vomiting.
  • Constipation.
  • Drowsiness.
  • Dizziness.
  • Lethargy.
  • Difficulty passing urine.
  • Dry mouth.
  • Sweating.
  • Headache.
  • Facial flushing.
  • Skin rashes.
  • Itching.
  • Changes in heart rate.
  • Awareness of your heartbeat (palpitations).
  • Paralytic ileus.
  • Toxic megacolon.
  • Low blood pressure (hypotension).
  • Changes in mood.
  • Increased pressure in the eye.
  • False perceptions of things that are not really there (hallucinations).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you take this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

This medicine should not be used by people who have taken any of the following medicines in the last 14 days: monoamine oxidase inhibitor antidepressants (MAOIs) eg phenelzine, tranylcypromine, isocarboxazid or moclobemide.

Diphenoxylate can reduce the muscular activity in the gut and so may counteract the effect of the following medicines on the gut:

  • cisapride
  • domperidone
  • galantamine
  • metoclopramide
  • neostigmine
  • pyridostigmine.

There may be an increased risk of antimuscarinic side effects, such as dry mouth, blurred vision or difficulty passing urine, if this medicine is used in combination with other medicines that have antimuscarinic effects, such as the following:

  • amantadine
  • antiarrhythmic medicines for irregular heartbeats, eg disopyramide, propafenone, quinidine
  • antihistamines, eg promethazine, brompheniramine, chlorphenamine, diphenhydramine, triprolidine (some of these are often found in over-the-counter cough and cold remedies)
  • antimuscarinic medicines for Parkinson's symptoms, eg procyclidine, orphenadrine, trihexiphenidyl
  • antimuscarinic medicines for urinary incontinence, eg oxybutynin, trospium, tolterodine
  • antipsychotics, eg chlorpromazine, clozapine, thioridazine
  • antisickness medicines, eg meclozine, cyclizine
  • antispasmodics, eg propantheline, hyoscine butylbromide
  • MAOI antidepressants, eg phenelzine
  • muscle relaxants, eg baclofen
  • tricyclic antidepressants, eg amitriptyline, clomipramine.

This medicine can decrease the amount of levodopa, available in the blood. This will reduce the therapeutic effects levodopa.

If you experience a dry mouth as a side effect of this medicine you may find that medicines that are designed to dissolve and be absorbed from under the tongue, eg sublingual glyceryl trinitrate (GTN) tablets, become less effective. This is because the tablets do not dissolve properly in a dry mouth. To resolve this, drink a mouthful of water before taking sublingual tablets.

Other medicines containing the same active ingredients

Co-phenotrope tablets are available without a brand name, ie as the generic medicine.