Treating diarrhoea

Assessing diarrhoea

Your doctor will ask you some questions, and they might do some tests. This is to find out the cause of your diarrhoea. Finding the cause is important.

Severe constipation can cause diarrhoea so your doctor might need to examine your tummy (abdomen) or your back passage (rectal examination) to rule this out.

If the diarrhoea is a side effect of your cancer treatment, your medical team might change the dose or the schedule of your treatment until your diarrhoea is better. This may mean having a break from cancer treatment for a few days or lowering the dose of treatment. In some situations they might have to stop the treatment you are having.

Replacing fluid loss

You can lose a lot of fluid very quickly when you have diarrhoea. You could get dehydrated if you lose too much fluid. Aim to drink at least 8 to 10 glasses of fluid each day. This can include tea, squash and milky drinks as well as soups, custard, jelly and ice lollies. Its best to avoid drinks that make you dehydrated such as alcohol, coffee and sugar free drinks.

If you are dehydrated your body fluids, salts, minerals and sugars need to be replaced until your diarrhoea stops.

Depending on how severe your diarrhoea is, this might mean:

• having fluids into your bloodstream as a drip into a vein (intravenous)- you might need to stay in hospital for this

• having drinks to replace the lost fluid that contain salts and minerals (if you are able to drink). You can purchase oral rehydration solutions in the pharmacy over the counter

The drinks contain sodium, potassium, and sugar to help replace what you have lost. Your doctor or nurse can keep a check on your fluid, salt and mineral levels by taking regular blood tests.

For severe diarrhoea you might have to stay in hospital as an inpatient for fluid replacement. And you may also have antibiotics if you have other symptoms such as a fever and signs of an infection.

Medicines to help with diarrhoea

Medicines that help to control diarrhoea are called anti diarrhoeals. There are several different types available from your local chemist without a prescription. But others need to be prescribed by your doctor.

Anti diarrhoea medicines

Loperamide is the main anti diarrheal medicine used to treat diarrhoea. Your doctor or pharmacist will tell you how much you should take and when to take it.

It works by slowing down the muscle movement in the gut. This means it takes longer for food to pass through your digestive system​ and more water is absorbed. This can help your poo to become firmer.

If diarrhoea is a known side effect of your cancer treatment, your doctor or nurse might give you anti diarrhoea medicines to take home with you after your treatment.

If your diarrhoea doesn't get better, you should let your doctor or nurse know as soon as possible. They may be able to suggest a different treatment.

Sometimes you might also have a painkiller called codeine phosphate alongside loperamide. You have this if loperamide alone isn’t working to stop your diarrhoea. Common side effects of loperamide include:

• constipation

• headache

• feeling sick

• passing wind

Speak to your doctor or nurse about the best time to take these medicines.

Medicines to reduce tummy spasms and cramps

You might have painful tummy spasms or cramps when you have diarrhoea. If you do your doctor might recommend you take medicines called anti muscarinics. These help to reduce tummy spasms and cramping. An example of these medicines is hyoscine butylbromide (Buscopan).

Medicines to stop the body losing water

You might have painful tummy spasms or cramps when you have diarrhoea. If you do, your doctor might recommend you take medicines called anti muscarinics. These help to reduce tummy spasms and cramping. An example of these medicines is hyoscine butylbromide, also known commonly by its brand name Buscopan.

Common side effects of these medicines include:

• dizziness

• drowsiness

• a dry mouth

• indigestion - symptoms include heartburn, bloating and burping

• episodes of feeling warm and reddening of the skin (flushing)

• headache

• feeling or being sick

• you might feel fluttering or pounding of your heart, or that it is beating fast

• you might have itching of the skin which may be red and raised

• sweating more than usual or lack of sweating

• being unable to pee

• your eyes might go red and you may have loss of vision

Medicines to stop the body losing water

Medicines called somatostatin analogues lower the amount of fluid produced by the gut. They can help to stop the body losing water and body salts (electrolytes). Octreotide and lanreotide are examples of somatostatin analogue drugs.

These medicines also slow down the time it takes for food to move through the digestive system.

Find out more about octreotide and it's side effects

Steroids

You might have steroids to help manage diarrhoea after treatment with checkpoint inhibitors.

Checkpoint inhibitors are a type of immunotherapy treatment. This treatment affects the immune system and can cause inflammation in different parts of the body including the digestive system, causing diarrhoea.

It is important to contact your healthcare team if you develop diarrhoea with immunotherapy treatment. Diarrhoea may need treatment. If it is not treated, it can become very serious and could be life‑threatening.

Steroids help control many body functions, including reducing inflammation.

The severity of the diarrhoea will affect how you have the steroids. You might take them by mouth, such as prednisolone. Or intravenously, such as methylprednisolone.

Find out more about having steroids and their side effects

A small number of people do not get better with steroids, so they might have another type of treatment called infliximab. It is a monoclonal antibody (mAb). If you are unable to have infliximab or infliximab doesn’t work, you might have vedolizumab.

Find out more about checkpoint inhibitors

Other ways to cope with diarrhoea

There are other ways to help cope with diarrhoea. We have information on:

• managing your diet

• soothing the skin around your back passage (anus)

• being prepared when you go out or are at home

Go to tips on coping with diarrhoea