Chemotherapy and Constipation

Prevention and Treatment

Constipation is a common side effect of chemotherapy or other medications prescribed during cancer treatment. Constipation is broadly defined as difficult or infrequent stool passage.

This article will review the symptoms of constipation, why it happens, and how to manage it.

Woman rubbing aching stomach
Tom Merton / Getty Images

Symptoms

Many people are familiar with the symptoms of constipation. These can include:

  • Less than three bowel movements a week
  • Dry, hard-to-pass stools
  • Straining during a bowel movement
  • The feeling of not emptying your bowels
  • Abdominal cramps
  • Swollen abdomen

Those undergoing chemotherapy or other medical treatments may not recognize these symptoms as constipation. They may experience only a decrease in appetite and a vague feeling of being unwell.

Causes

Several different factors can lead to constipation during chemotherapy. These include:

  • Chemotherapy medications
  • Medications used to treat nausea and vomiting
  • Decreased activity
  • Pain medication
  • Dehydration
  • Thyroid problems

Chemotherapy medications often associated with the development of constipation include:

  • Thalidomide
  • Cisplatin
  • Vincristine
  • Vinblastine
  • Vinorelbine

Diagnosis

The diagnosis of constipation during chemotherapy is made based on symptoms someone is experiencing in combination with determining other risk factors.

How To Manage Constipation

Constipation can be managed in a variety of ways. An important first step is to notify the healthcare provider that constipation is occurring. It helps to be thorough when listing your medications to your healthcare provider because many medications used in cancer treatments and pain relief can cause constipation. These questions will help determine the exact cause of constipation.

Fluid Intake

Increasing fluid intake can be an effective treatment for constipation. Drinks like water and juices are recommended. Avoid drinks that contain caffeine, (like sodas or coffee) and alcohol, because they can cause dehydration, which could worsen constipation.

Dietary Fiber

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 healthcare provider. 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 bread, pasta, and many fruits and vegetables are all high-fiber foods that can help prevent constipation.

Once someone is very constipated, adding in high-fiber foods may increase discomfort until constipation has been relieved.

Talk to your healthcare provider 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. Nutritional labels will list fiber content, and fiber content of unprocessed foods can be found in online resources.

Exercise

Exercise is very important when going through treatment. Taking short, regular walks can help to prevent and relieve constipation. For those who have decreased mobility, moving from a chair to the bed can activate abdominal muscles and help with constipation.

Before starting any exercise, no matter how little you think it may be, talk to your healthcare provider. They can recommend exercises and help guide you in how much you should do.

Medications

Several categories of medications work for constipation. Some medications may work better than others for particular causes of constipation, so it's important to talk to your healthcare provider and get their recommendation. Some medications are a combination of two or more treatments, designed to both soften the stool and help it pass through the body.

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 medications 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 a bulk-forming laxative is Metamucil (psyllium).
  • Stimulant laxatives: Stimulants work directly on the nerves around the colon to stimulate the movement of stool through the intestines. Because 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 Miralax (polyethylene glycol 3350), 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 decrease transit time, so they are often used along with another medication to facilitate a bowel movement if these have become infrequent. An example of an emollient 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

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

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 healthcare provider manually.

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

Summary

Constipation is a commonly experienced side effect during cancer treatment, and may occur due to a variety of reasons, one of which is the chemotherapy itself.
Managing constipation can be done through dietary changes, increased fluid intake, and medications. Increasing activity and exercise can also improve constipation.

Frequently Asked Questions

  • Why do chemotherapy drugs cause constipation?

    Chemotherapy can effect the nerves in the intestine, potentially slowing down the movement of stool through them. It can also effect the nerve endings in the rectum, which could make it difficult to pass stool.

  • How long does constipation last after chemotherapy?

    If the constipation was caused directly by the chemotherapy, the symptom may improve in a few weeks after treatment has completed. If there were other factors, such as the use of pain medications or decreased activity, it may take longer for constipation to improve.

Was this page helpful?
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bharucha AE, Pemberton JH, Locke GR 3rd. American Gastroenterological Association technical review on constipation. Gastroenterology. 2013;144(1):218-238. doi:10.1053/j.gastro.2012.10.028

  2. McQuade RM, Stojanovska V, Abalo R, Bornstein JC, Nurgali K. Chemotherapy-induced constipation and diarrhea: pathophysiology, current and emerging treatmentsFront Pharmacol. 2016;0. https://doi.org/10.3389/fphar.2016.00414

  3. American Society of Clinical Oncology, Cancer.net. Constipation.

  4. National Cancer Institute. Constipation: cancer treatment side effect.

  5. National Institutes of Health: National Cancer Institute. Gastrointestinal complications (PDQ®)–Patient version.

  6. Academy of Nutrition and Dietetics: EatRight. Easy ways to boost fiber in your daily diet.