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Constipation in Childhood Cancer

What Is Constipation?

Constipation is a condition where stool (poop) is hard, difficult to pass, or moves too slowly through the digestive tract. This can make bowel movements less regular and lead to problems such as pain, loss of appetite, hemorrhoids, and breaks or tears in the skin.

Constipation is a common side effect of cancer and cancer treatments. It can cause discomfort, interfere with daily activities, and reduce quality of life. Severe constipation can lead to fecal impaction, a condition where a hard mass of stool becomes stuck in the colon or rectum. Hard stools can also cause cuts or tears in the skin in or around the anus. These tears are called anal fissures. For children with cancer and weak immune systems, these breaks in the skin can lead to serious infection.

Constipation is something that children, and especially teens, may not want to talk about. However, there are ways to manage constipation. Changes in diet, drinking fluids, and being physically active may help. The care team may also recommend certain medicines to help with constipation.

Symptoms of Constipation in Kids

  • Stool that is hard, dry, or lumpy
  • Stool that is larger than normal or is in small pieces
  • Having fewer bowel movements than normal
  • Straining or not being able to push out stool
  • Taking a long time in the bathroom
  • Abdominal pain
  • Feeling like you still have to go after a bowel movement
  • Having a swollen belly or feeling full or bloated
  • Loss of appetite
  • Seeing small amounts of blood on toilet paper after wiping
  • Having stool or stool marks on underwear
  • Being irritable, crying, or avoiding using the toilet

Diagnosing Constipation

Bowel habits are different for everyone. However, bowel movements should generally occur 3 or more times per week.

Diagnosis of constipation considers:

  • Frequency of bowel movements (2 or less per week)
  • Appearance of stool (hard, dry, lumpy, or large in diameter)
  • Effort to pass stool (pain or straining with bowel movement)

A medical exam for constipation may include:

  • A health history and review of toileting habits
  • Feeling the abdomen
  • Exam of the anal area
  • Laboratory tests of blood and stool
  • Reflex and muscle tests
  • Imaging tests

Causes of Constipation in Childhood Cancer

As food moves through the digestive tract, nutrients and water are absorbed. Waste is passed out through the colon and rectum as stool. Sometimes, the digestive system slows down, and the stool moves through the intestines too slowly. This can allow more water to be absorbed, making stools hard and dry.

Several factors may lead to constipation during cancer treatment. These include:

  • Low fiber diets
  • Decrease in food intake
  • Low fluid intake or dehydration
  • Physical inactivity
  • Pressure on stomach or intestines due to the tumor
  • Medicines for pain or nausea
  • Some chemotherapy medicines
  • Other medical conditions such as diabetes, hypothyroidism, or celiac disease

Medicines that Cause Constipation

A common side effect of some medicines is constipation. For children with cancer, medicines that often cause constipation are pain medicines and anti-nausea medicines. Constipation is a side effect of some chemotherapy drugs like vincristine and vinblastine. Children treated with iron supplements for anemia may also experience constipation.

Types of medicines most likely to cause constipation include:

  • Pain medicines including opioid medicines and NSAIDS
  • Anti-nausea medicines
  • Antacids
  • Diuretics
  • Allergy medicines including antihistamines
  • Antidepressant medications
  • Iron supplements

Why Do Opioids Cause Constipation?

Opioid medicines are often given to help control pain during pediatric cancer treatment. Some of these medicines are codeine, fentanyl, hydrocodone, methadone, morphine, and oxycodone. Opioid medicines can cause constipation in a few ways:

  1. Opioids can slow down the movement of the intestines. This slows the travel of waste through the digestive system.
  2. Opioids can decrease fluid in the intestines. This can cause stool to become dry and hard.
  3. Opioids can decrease muscle tone and weaken reflexes that control the elimination of stool. This can make it hard to push the stool out.

Because constipation is a common side effect, the care team may recommend a laxative to prevent constipation if an opioid is prescribed.


Treatments for Constipation

There are several ways to help prevent and treat constipation in pediatric cancer patients. It is important for families to work closely with the care team to make sure that children’s symptoms are managed. Mild constipation is usually first treated with diet and other behavior changes such as drinking more water and increasing physical activity. The next step in treatment is usually medicine to encourage a bowel movement.

Medicines for Constipation

Medicines for constipation are often called laxatives. Laxatives can work in different ways such as by softening the stool or stimulating a bowel movement.

  • Stool softeners (docusate) increase the water and fat content in the stool to make it softer.
  • Osmotic laxatives (Miralax®, lactulose) increase the fluid in the gastrointestinal tract to decrease constipation.
  • Stimulant laxatives (senna, bisacodyl) increase contractions of the muscles that line the intestines to help stool travel through the digestive tract.
Osmotic laxatives/ Stool softeners Stimulant laxatives Combination medicines
Polyethylene glycol 3350 (MiraLax®) Senna (Ex-Lax®, Senexon®, Senokot®) Senna + Docusate (Correctol 50 Plus®, Ex-Lax Gentle Strength®, Peri-Colace®, Senokot S®)
Docusate (Colace®, Pedia-Lax®) Bisacodyl (Correctol®, Dulcolax®)  
Note: It is important to read the ingredients on laxative labels. Many popular brand names have multiple formulas that work in different ways. The brand names are for example purposes only.

Medicines for constipation are often taken by mouth. Laxatives may sometimes be given as a rectal suppository or enema, but these should only be used if instructed by a doctor.

Many laxatives are available over the counter without a prescription. However, it is very important to talk with the care team before taking any medicine. Laxatives can cause problems such as nausea, cramping, diarrhea, and dehydration when not used properly.

If constipation is caused by opioids, a medicine called methylnaltrexone (Relistor®) may be given to help relieve constipation caused by opioids. The care team may also consider changes to the pain treatment plan.

Changes in Diet to Help Constipation

Nausea, loss of appetite, and fatigue can make it hard for patients to eat enough calories and high fiber foods during cancer treatment. Some diet changes to help constipation include:

  • Eat foods high in fiber. High fiber foods include fruits, vegetables, whole grains, beans, and nuts.
  • Drink plenty of fluids.
  • Eat regular meals.
  • Have a warm beverage or warm oatmeal for breakfast. The warm temperature can help stimulate the digestive tract.

Find more nutrition tips to help with side effects.

Some ways to prevent and treat these problems include:

  • Avoid straining, and limit the time spent sitting on the toilet.
  • Wipe the area gently, but make sure to clean thoroughly. It may help to use moist toilet paper or unscented bathroom wipes.
  • Take a warm bath, or apply a warm cloth to the area.
  • Apply a cream as recommended by your doctor or pharmacist.

Constipation in Children with Cancer: Tips for Families

  • Prepare your child for the possibility of constipation and other common side effects. Help your child learn about his or her body in age-appropriate ways, and keep communication honest and open.
  • Talk about problems such as anal fissures and hemorrhoids, and make sure that older children and teens know signs and symptoms. Stress the importance of letting the care team know if they occur.
  • Discuss constipation with your care team. There are medicines and other strategies that can help.
  • Keep a record of toileting habits. Write down how often, how much, and what stool looks like. Make sure to note pain or straining. This can help your doctor better understand the problem.
  • Offer high-fiber foods. Let your care team know if your child is having problems eating or drinking.
  • Encourage physical activity as much as possible.
  • Follow dosing instructions for laxatives.

More Resources on Constipation in Children with Cancer

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Reviewed: February 2019