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How to Treat Diarrhea Caused by Your Treatments and Medications

Diarrhea is when you have more than two loose or watery stools (“poops”) each day. Diarrhea is a common side effect of cancer treatments.

Patient handout: Diarrhea Caused by Medications

Diarrhea is when you have more than two loose or watery stools (“poops”) each day. Diarrhea is the opposite of constipation (hard or infrequent stools).  

Diarrhea can be acute (short-lasting) or chronic (long-lasting).  
Diarrhea is a common side effect of cancer treatments. 

Diarrhea can be caused by 
  • radiation near your bowels
  • some chemotherapies
  • targeted therapies
Some medications, like antibiotics, can also cause diarrhea.

It is very important to manage diarrhea. Diarrhea can cause: 
  • Dehydration (lack of water) 
  • Depletion of body salts (not enough salts in the body)
  • Weakness
  • Weight loss
  • Skin soreness
  • Poor nutrition.
Diarrhea can also delay your cancer treatments.
 
 

‎Tell your health care team if you have diarrhea. They will work with you to figure out what is causing the diarrhea and how to manage it.


Call your health care team right away if:

  • Your stool has blood or mucus in it.
  • You have watery stools more than twice a day.
  • You have a temperature of 100.5F (38◦C) or higher.
  • You have very painful cramping and /or very painful stomach (abdominal) pain.
  • You are throwing up (vomiting) a lot and cannot eat or drink without throwing up.
  • You are very, very thirsty.
  • You get dizzy and weak.
  • Your urine ("pee") is dark yellow and you are not going pee as often as you usually do.
  • You have pain in your upper right abdomen, under your ribs.

Talk to your health care team before taking any anti-diarrheal medications. They need to make sure your diarrhea is not caused by an infection.


Your health care team may recommend a medication called loperamide (Imodium®). You can buy loperamide at a pharmacy without a prescription.

How to take loperamide:

  1. If you have diarrhea, take 4mg of loperamide. 
  2. If you still have diarrhea four hours after taking loperamide, take 2mg more of loperamide. Only take more loperamide if you still have diarrhea 4 hours after your first 4mg dose. 
  3. Take 2mg of loperamide every 4 hours if you still have diarrhea.
Do not take more than 14mg of loperamide in total in 24 hours. 

The directions on the loperamide package may be different. This is ok. Follow the directions in this handout.
If you still have diarrhea after taking loperamide for 24 hours, as written above, call your health care team. You may need a higher dose of loperamide or another medication.

If you start having watery stools after being constipated, it may be because there is hard stool stuck in your rectum (“bum”). This is called impaction. If this happens to you, do not take pills for diarrhea. Call your health care team.

If you follow the instructions in this handout and your diarrhea is still not under control, ask to see a BC Cancer dietitian.  

If you are losing weight or you do not have an appetite, ask to see a BC Cancer Dietitian. 

‎If you are having diarrhea, here are some things you can do:

  • If you have to stay in bed, use a bedside commode (portable toilet) when possible. 
  • Keep a record of your bowel movements ("poops") and what you eat.
  • Keep a list of foods that cause you more problems and try not to eat them. 
  • Eating can often trigger a bowel movement. Try to schedule activities so you have enough time to go poop before planned activities.

Take care of your skin

When you have diarrhea, the skin around your anus (opening to your “bum”), can get irritated and sore.  

To protect your skin, keep the anal area clean with soap and water. 

If your skin has broken down (you have open sores or chapped skin) you can use a special cleanser. Ask your health care team if you do not know what cleanser to use. 

You can also take sitz baths (warm, shallow baths) to soothe the area. Ask your health care team for more information about this.

Food ideas to help with diarrhea 

  • You may find the following nutrition tips helpful:
  • Drink at least 1.5 – 2 litres (6-8 cups) of fluids every day. This will help keep you hydrated. It may help to sip fluids slowly. 
  • Examples of fluids are water, juice, liquid nutritional drinks such as Ensure®, sports drinks, soups or broths and herbal tea. Limit drinks with caffeine and alcohol. These can bother your bowels.
  • Eat small, frequent meals and snacks. Try to eat every 2-3 hours.
  • Try not to eat too many high-fibre foods such as whole grain breads and cereals with bran, nuts, and seeds. Choose white bread or pasta, white rice, meat, poultry, eggs, and tofu. 
  • Remove skins, seeds and fibres from fruits and vegetables. 
  • Try not to eat too much corn, broccoli, beans, green leafy vegetables, prunes, berries, dried fruit, chickpeas and lentils.
  • Do not eat spicy, deep-fried, or greasy foods.
If it makes your diarrhea worse, do not eat or drink milk and milk products. Lactaid® milk or milk substitutes, such as soy drinks, may be better for you.

If you are not sure what to eat or drink, talk to your health care team.

People with severe dehydration may need to get intravenous fluids (fluids given to you by putting a needle attached to a tube into your vein).

If you follow the instructions in this handout and your diarrhea is still not under control, ask to see a BC Cancer dietitian.  

If you are losing weight or you do not have an appetite, ask to see a BC Cancer Dietitian. 

You can also call 8-1-1 to speak to an oncology dietitian at Health Link BC.

Probiotics

There is not enough evidence to support the use of probiotics. Although probiotics might benefit you, there is a risk for patients with neutropenia (low white blood cell count).  

If you have neutropenia, your immune system is not working as well as it should. The bacteria in probiotics could give you an infection.

Revised February 2020

SOURCE: How to Treat Diarrhea Caused by Your Treatments and Medications ( )
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