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Cancer Health Center

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Gastrointestinal Complications (PDQ®): Supportive care - Patient Information [NCI] - Constipation

With constipation, bowel movements are difficult or don't happen as often as usual.

Constipation is the slow movement of stool through the large intestine. The longer it takes for the stool to move through the large intestine, the more it loses fluid and the drier and harder it becomes. The patient may be unable to have a bowel movement, have to push harder to have a bowel movement, or have fewer than their usual number of bowel movements.

Certain medicines, changes in diet, not drinking enough fluids, and being less active are common causes of constipation.

Constipation is a common problem for cancer patients. Cancer patients may become constipated by any of the usual factors that cause constipation in healthy people. These include older age, changes in diet and fluid intake, and not getting enough exercise. In addition to these common causes of constipation, there are other causes in cancer patients.

Other causes of constipation include:

  • Opioids and other pain medicines. This is one of the main causes of constipation in cancer patients.
  • Chemotherapy.
  • Medicines for anxiety and depression.
  • Antacids.
  • Diuretics (drugs that increase the amount of urine made by the body).
  • Supplements such as iron and calcium.
  • Sleep medicines.
  • Drugs used for anesthesia (to cause loss of feeling for surgery or other procedures).
  • Not drinking enough water or other fluids. This is a common problem for cancer patients.
  • Not eating enough food, especially high-fiber food.
Bowel movement habits
  • Not going to the bathroom when the need for a bowel movement is felt.
  • Using laxatives and/or enemas too often.
Conditions that prevent activity and exercise
Intestinal disorders
Muscle and nerve disorders
  • Brain tumors.
  • Spinal cord injury or pressure on the spinal cord from a tumor or other cause.
  • Paralysis (loss of ability to move) of both legs.
  • Stroke or other disorders that cause paralysis of part of the body.
  • Peripheral neuropathy (pain, numbness, tingling) of feet.
  • Weakness of the diaphragm (the breathing muscle below the lungs) or abdominal muscles. This makes it hard to push to have a bowel movement.
Changes in body metabolism
  • Having to go farther to get to a bathroom.
  • Needing help to go to the bathroom.
  • Being in unfamiliar places.
  • Having little or no privacy.
  • Feeling rushed.
  • Living in extreme heat that causes dehydration.
  • Needing to use a bedpan or bedside commode.
Narrow colon
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