Chemotherapy and Constipation

What You Can Do to Prevent and Treat Constipation During Chemotherapy

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Constipation is a common side effect of chemotherapy or other medications prescribed during cancer treatment.  Constipation is defined as having hard or infrequent stools or difficulty in having a bowel movement.

Symptoms of Constipation During Chemotherapy

Many people are familiar with the symptoms of constipation.  These can include abdominal cramping, a sense of fullness in the abdomen, rectal pain, and of course you may notice that you haven't had a bowel movement for 2 or 3 days if you are usually regular.

  The symptoms, however, are not always obvious to those going through chemotherapy or coping with other medical conditions.  They may include only a decrease in appetite and a vague feeling of being unwell - symptoms that are common with cancer to begin with.

What Causes Constipation During Chemotherapy?

There are several different factors which can lead to constipation during chemotherapy.  These include:


Most of the time the diagnosis of constipation during chemotherapy can be determined based on symptoms alone in combination with medications that raise the risk.

How to Manage Constipation During Chemotherapy

The first thing you should do is to talk to your doctor. Tell him that you are experiencing constipation or hard/infrequent stools.

Your doctor will likely want to know about your eating habits if you have taken any over-the-counter laxatives, enemas, or suppositories, and confirm medications you are taking. It helps to be especially assertive when listing your medications to your doctor since many medications used in cancer treatments and pain relief can cause constipation.

These questions will help determine the exact cause of the constipation.

Fluid Intake

Many patients report some relief when increasing the amount of fluids they drink. Drinks like water and juices are recommended. Avoid drinks that contain caffeine, like sodas, coffee, and alcohol, because they can cause dehydration, which could worsen constipation.

Increase Fiber in Your Diet

For mild cases of constipation, increasing fiber in the diet can be all the body needs to have regular bowel movements. Before increasing fiber in the diet, ask your physician. Some patients should not have increased fiber, such as those who have had a bowel obstruction or bowel surgery.

Increasing the amount of fiber starts with the foods you eat. Nuts, bran, vegetables, legumes, whole wheat breads and pastas, and many fruits and vegetables are all high-fiber foods that can help prevent constipation.  In one recent study, sweet potatoes were found to be particularly effective in preventing constipation.

It's important to note, however, that once someone is very constipated, adding in high fiber foods may increase discomfort until the constipation has been relieved.

Talk to your doctor about how much fiber you should be getting daily. The suggested dietary intake for healthy women is 21-25 grams and men should consume 30-38 grams per day. You can find out how much fiber is in a certain food by reading the label on the packaging or looking it up online in the case of foods that aren't labeled such as fruits and vegetables.


Exercise is still very important when going through treatment. Something as simple as going for a short, regular walk can help to prevent and relieve constipation. For those who are bed ridden, moving from a chair to the bed can help because it utilizes the abdominal muscles

Before starting any exercise, no matter how little you think it may be, talk to your doctor. He or she can recommend exercises and tell you just how much you should be getting.

Medications for Constipation During Chemotherapy

There are several categories of medications which work for constipation in different ways.  Some of these may work better than others for particular causes of constipation, so it's important to talk to your doctor and get her recommendation.  Some medications come with a combination of two or more of these drugs, designed to both soften the stool and aid in its evacuation.

With some chemotherapy regimens, the combination of drugs, especially drugs to prevent nausea. are very constipating, and your oncologist may recommend using medications for constipation preventively  Make sure to do so, as it is easier to prevent than treat severe constipation.  Also, make sure to talk to your oncologist before using any medications, as some of these have the potential to interfere with chemotherapy drugs.  Some treatments include:

  • Bulk-forming laxatives - These medications work to draw water back into the intestine to decrease the hardness of the stool, as well as by decreasing transit time - the amount of time that stool stays in the colon.  An example of this category is Metamucil (psyllium).
  • Stimulant laxatives - Stimulants work directly on the nerves around the colon to stimulate transit of stool through the gastrointestinal tract.  Since it can be painful when very hard stools pass through the colon, these are often given along with a stool softener.  Examples of stimulant laxatives include Senekot (senna) and Dulcolax (bisacodyl).
  • Osmotic laxatives - Osmotic laxatives work to keep fluids in the colon and also stimulate peristalsis - the rhythmic contractions of the colon that move stool forward.  Examples include Chronulac (lactulose), glycerin suppositories, Miralax (polyethylene glycol), magnesium citrate and Milk of Magnesia (magnesium hydroxide.)
  • Emollients/Stool softeners - Stool softeners soften the stool by working with the mix of water and fat in the stool.  These medications soften the stool but do not increase transit time, so they are often used along with another medication to facilitate a bowel movement if these have become infrequent.  An example of these is Colace (docusate).
  • Lubricants - These medications bring water into the stool to soften it and also lubricate the stool for passage out of the body.  Mineral oil is an example.

Manual Removal - Digital Evacuation

When all else fails, if fecal impaction occurs, or if constipation is very painful, digital evacuation may need to be done.  This refers to the manual removal of stool using gloved fingers.

Complications of Chemotherapy Induced Constipation

Chronic severe constipation can lead to fecal impaction, a condition in which hard, dry fecal matter that develops in the rectum and cannot be passed. The impacted feces are then removed by the doctor manually.

Other complications from chronic constipation include hemorrhoids, anal fissures, perianal absceses, and rectal prolapse.


American Society of Clinical Oncology. Cancer.Net. Constipation. Updated 01/16.

National Cancer Institute. Gastrointestinal Complications – Health Professional Version. Updated 01/04/16.

Zou, J., Xu, Y., Wang, X., Juang, Q., and X. Zhu. Improvement of Constipation in Leukemia Patients Undergoing Chemotherapy Using Sweet Potato. Cancer Nursing. 2015 Apr 15. (Epub ahead of print).

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