Diarrhea is an unpleasant but common side effect in people receiving treatment for cancer. Diarrhea may also be caused by the cancer itself. Diarrhea can be more than an inconvenience for people with cancer 

Chemotherapy drugs may cause digestive upsets, including nausea, vomiting, constipation, and diarrhea. If you have cancer, there are the things that normally cause diarrhea can still affect you. But there are additional causes of diarrhea in people with cancer, such as:

  • Cancer treatment. Some cancer treatments can cause diarrhea, including chemotherapy, radiation, surgery (if certain parts of the intestine need to be removed) and bone marrow transplants.
  • Infections. Cancer treatment can make you more susceptible to various infections, which can cause diarrhea. Antibiotics used to treat some infections also can cause diarrhea.
  • Cancer itself. Certain cancers can cause diarrhea, including hormone-producing (neuroendocrine) tumors, such as carcinoid syndrome and Zollinger-Ellison syndrome; colon cancer; lymphoma; medullary carcinoma of the thyroid gland; and pancreatic cancer.

The duration and severity of your diarrhea depend on what’s causing your signs and symptoms. Talk to your doctor about what you can expect and how long your diarrhea may last.

Chemotherapy damages rapidly dividing cells. Cancer cells tend to divide rapidly and uncontrollably. However, some healthy cells also divide rapidly, such as those that line the interior of the digestive tract. Chemotherapy also damages these cells, leading to a disruption in the delicate fluid balance that they maintain. Specifically, absorption of fluid from the gastrointestinal (GI) tract back into the body is decreased and secretion of fluid and electrolytes in the stool is increased. This causes watery bowel movements, the definition of diarrhea.

Many cancer patients experience diarrhea while they’re undergoing chemotherapy treatment. These tips can help you cope with diarrhea.

Diarrhea is a liquid-like loose stool. At the first sign of poorly formed or loose stools, or if you notice you are having more bowel movements than usual, you should begin taking Imodium (Loperamide).

    • Take two caplets (4 mg) followed by one caplet (2 mg) every two hours until you have had no diarrhea for 12 hours.
    • During the night, take two caplets (4 mg) at bedtime and continue every four hour during the night until morning.
    • Stop taking Imodium only after there is no sign of diarrhea for 12 hours.

What to drink if you have diarrhea

    • Drink at least six to eight large glasses of decaffeinated fluid a day.
    • Drink a little at a time as often as you can. Water, clear soups, and Gatorade are all good.

What not to eat or drink

    • Don’t drink milk, coffee and alcohol. Avoid very hot or very cold fluids.
    • The following foods can make diarrhea or cramping worse: fatty, fried or greasy foods, spicy foods, high-fiber foods, bran and some cereals, raw fruits and vegetables, dried fruits, beans, popcorn, nuts, and chocolate.

Modify your diet

Think BRAT. The BRAT diet is a simple, gentle and effective way to ease intestinal upset that causes diarrhea.

    • Eat small meals that include:
    • B-Bananas
    • R-Rice
    • A-Applesauce
    • T-Tea (decaffeinated) and Toast

The diet is fat-free and easily digested. You do not need to eat all these foods at any one meal; any combination is fine. You could have tea and toast for breakfast, applesauce and toast for lunch, and banana slices and rice for dinner.

If you do well on these foods, you can start adding others, like:

    • Bland low-fiber foods
    • White-meat chicken without the skin
    • Crackers, white bread, and pasta without sauce
    • Canned or cooked fruits without skin

Diet: Several modifications to diet will help reduce the discomfort of diarrhea. Foods that irritate the GI system should be avoided, such as greasy, spicy or fried foods. You should also avoid milk and milk products because diarrhea may lead to a loss of the enzyme lactase which breaks down lactose, the sugar found in milk, resulting in temporary lactose-intolerance. Because of their high fiber content, vegetables tend to be difficult to digest and should be avoided during episodes of diarrhea. Cruciferous vegetables, such as cabbage, Brussels sprouts and broccoli, can be particularly problematic.

Your diet should be limited to simple, easy to digest foods, then expanded as the diarrhea begins to subside. A diet consisting of bananas, rice, applesauce, toast (called the BRAT diet) and clear liquid is a good starting point. Eventually, pasta without sauce, white-meat chicken without skin, scrambled eggs and other easily digested foods can be added, as tolerated.

Fluid intake: Staying hydrated is very important in the management of diarrhea. You must consume enough clear liquids to make up for the volume of fluids lost due to diarrhea. This amount is in addition to the usual daily intake. You may need to take in 3-4 liters or more of fluid per day. In addition to plain water, you should include fluids that contain some sugar and salt, such as broth or Gatorade. Replacement of fluids with plain water alone can lead to low levels of salt or calcium in the blood. These can be life-threatening conditions.

Drug therapy: The first drug to be prescribed for chemotherapy-related diarrhea is usually loperamide (Imodium® or others). Loperamide slows the gastrointestinal system and reduced the amount of fluid lost in the stool. Loperamide is effective for managing mild to moderate diarrhea, though it may not work for severe diarrhea. It is an over-the-counter medication that is inexpensive and is available as a pill.

Diarrhea is an extremely common side effect of chemotherapy. Digestive problems like diarrhea occur because of how chemotherapy drugs are designed to work. Cancer cells divide quickly — faster than most of the cells in our body. Chemotherapy drugs work by targeting these rapidly dividing cells. But some normal cells in our bodies also rapidly divide, including our hair follicle cells and the cells in the lining of our stomach and digestive tract. Chemotherapy drugs simply cannot tell the difference between these normal, rapidly dividing cells and cancer cells, so the drugs attack these cells as well. This is why we experience hair loss and digestive problems when undergoing chemotherapy.

First, you should know that reporting any side effects to your doctor is essential during treatment — even those that you may find to be unrelated to treatment. Diarrhea can become serious, especially because it can quickly lead to dehydration. When you have a runny bowel movements, you are losing a lot of fluids with each episode. The good news is that your doctor will likely prescribe a medication to help prevent and treat diarrhea.

Eating Well During Chemotherapy

Appetite loss is very common and can occur anytime during treatment, so take advantage of your appetite while you have it! Remember to eat well-balanced meals that consist of lean protein, colorful fruits and vegetables, and lots of caffeine-free liquids.

Eating well is essential during treatment, especially when you suffer from diarrhea. There are foods that you can eat to help relieve it. The key is to consume foods that are low-fiber or have pectin, a soluble fiber. Potassium-rich foods are also good.

Recommended Foods When Experiencing Diarrhea

  • bananas
  • white rice
  • noodles
  • creamed cereals
  • cottage cheese and yogurt are acceptable dairy foods, while others should be avoided.
  • applesauce, peach and apricot nectar and other cooked or canned fruit without skin
  • white bread
  • potatoes
  • skinless white meat including chicken, turkey, or fish
  • If you continue to have diarrhea, avoid the following foods:
  • greasy, fatty foods
  • sugary foods to include jellies, candy, jams, and fruit juices
  • foods containing dairy (butter, milk, cheese, ice cream, etc)
  • carbonated beverages
  • beans, nuts, and seeds
  • cruciferous vegetables
  • alcohol (can irritate the digestive tract; alcohol is generally not recommended during treatment)
  • coffee and tea
  • artificial sweeteners (can cause diarrhea in some people)

Just remember that your digestive system is very sensitive right now and will continue to be during treatment. Even if your appetite hasn’t changed, you have to be careful of the foods you consume because they may upset your stomach, even if they didn’t prior to treatment.

Staying Hydrated Is Key When Experiencing Diarrhea

As mentioned above, when you have diarrhea, you lose vital fluids with each bowel movement. Replacing those lost fluids is essential and should be done by drinking clear fluids in addition to your recommended daily intake of water. Gatorade, Powerade, and even Pedialyte are excellent rehydration fluids because they contain glucose and sodium that will help regain adequate electrolyte levels. By drinking additional plain water to replace lost fluids, you may decrease sodium and calcium levels in the body, which can be dangerous.

Diarrhea is not only inconvenient side effect of cancer treatment, but also can be life-threatening if not adequately managed. It may lead to dehydration; electrolyte imbalance; low immune function; malnutrition due to reduced absorption of nutrients; and inflammation, pain and/or bleeding as a result of the increased frequency of bowel movements.

At its extreme, diarrhea can cause the critical electrolytes sodium and potassium to reach dangerously low levels, which are conditions known as hyponatremia and hypokalemia, respectively. The body continually regulates sodium in order to maintain levels within a narrow range. Diarrhea can disrupt this delicate balance by excreting too much sodium in the stool. Symptoms of mild low sodium levels include tiredness, disorientation, headache, muscle cramps and nausea. Severely low sodium levels can lead to seizures or coma. Severely low levels of potassium can cause abnormal heart function.

Diarrhea can be severe enough that you are unable to tolerate your prescribed chemotherapy treatments. Commonly, chemotherapy treatments are delayed if diarrhea persists. A disruption or delay in treatment may diminish the effect of treatment.

  • Actinomycin (Cosmegen®)
  • Altretamine (Hexalen®)
  • Arsenic trioxide (Trisenox®)
  • Bortezomib (Velcade®)
  • Busulfan (Myleran®, Busulfex®)
  • Capecitabine (Xeloda®)
  • Docetaxel (Taxotere®)
  • Floxuridine (FUDR®)
  • Flutamide (Eulexin®)
  • Fulvestrant (Faslodex®)
  • Gefitinib (Iressa®)
  • Gemtuzumab ozogamicin (Mylotarg®)
  • Idarubicin (Idamycin®, Idamycin PFS®)
  • Imatinib mesylate (Gleevac®, Glivec®)
  • Interleukin-2 (Proleukin®)
  • Irinotecan (Camptosar®)
  • Liposomal daunorubicin (DaunoXome®)
  • Mitotane (Lysodren®)
  • Oprevelkin (Neumega®)
  • Paclitaxel (Taxol®, Onxal®)
  • Pemetrexed (Alimta®)
  • Plicamycin (Mithracin®)
  • Sagramostim (GM-CSF, Leukine®)
  • Teniposide (Vumon®)

The cancer treatments that have been reported to cause diarrhea in 10-29% of patients are:

  • Abarelix (Plenaxis®)
  • Carboplatin (Paraplatin®)
  • Celocoxib (Celebrex®)
  • Cyclophosphamide (Cytoxan®, Neosar®)
  • Darbepoetin alpha (Aranesp®)
  • Daunorubicin (Cerubidine®)
  • Denileukin diftitox (Ontak®)
  • Epirubicin (Ellence®)
  • Estramustine (Emcyt®)
  • Etoposide (VePesid®, Toposar®, Etopophos®)
  • Fludarabine (Fludara®)
  • Gemcitabine (Gemzar®)
  • Hydroxyurea (Hydrea®)
  • Ibritumomab (Zevalin®)
  • Interferon alpha (Intron®, Roferon-A®)
  • Liposomal doxorubicin (Doxil®)
  • Mechlorethamine (Mustargen®)
  • Melphalan (Alkeran®)
  • Methotrexate (Rheumatrex®, Trexall®)
  • Mitomycin (Mutamycin®)
  • Mitoxantrone (Novantrone®)
  • Oxaliplatin (Eloxatin®)
  • Pentostatin (Nipent®)
  • Procarbazine (Matulane®)
  • Rasburicase (Elitek®)
  • Streptozocin (Zanosar®)
  • Thalidomide (Thalomid®)
  • Topotecan (Hycamtin®)
  • Tositumomab and iodine 131 (Bexxar®)
  • Vinblastine (Velban®, Alkaban-AQ®)
  • Vincristine (Oncovin®, Vincasar PFS®)
  • Vinorelbine (Navelbine®)

Certain medicines can cause diarrhea, including antibiotics and laxatives. Anti-emetics such as metoclopramide (Maxeran) and prokinetic agents can also cause diarrhea. Certain chemotherapy drugs are also known to cause diarrhea. These include:

  • irinotecan (Camptosar)
  • 5-fluorouracil (Adrucil, 5-FU)
  • methotrexate
  • docetaxel (Taxotere)
  • cisplatin (Platinol AQ)
  • dactinomycin (Cosmegen, actinomycin-D)
  • doxorubicin (Adriamycin)
  • arsenic trioxide
  • gefitinib (Iressa)
  • oxaliplatin (Eloxatin)
  • capecitabine (Xeloda)

Some factors may make chemotherapy-related diarrhea worse. For example, damage to the intestines as a result of surgery or radiation may make the GI system more susceptible to irritation. Other medications, such as antibiotics, diabetes, irritable bowel syndrome, reduced pancreas function or other conditions, may also worsen diarrhea. If you have certain biochemical characteristics, you may be more sensitive to chemotherapy drugs.

Sensitivity to 5-FU: Some individuals are more sensitive to 5-FU because they have significantly less of the enzyme that breaks down this drug. These individuals experience more side effects from treatment with 5-FU including diarrhea, low white blood cell count and mouth sores.

Sensitivity to irinotecan: Some individuals are more sensitive to the drug irinotecan due to a genetic disorder called Gilbert’s Syndrome that limits their ability to remove the drug from their body. This syndrome is difficult to detect before administration of irinotecan. If you experience severe side effects after your first dose of irinotecan, Gilbert’s syndrome may be the cause. Irinotecan should be either discontinued or the doses should be substantially reduced if Gilbert’s syndrome is suspected.

Another cause of sensitivity to irinotecan is obstruction of the vessel that delivers bile from the gallbladder to the intestines, called biliary obstruction. As with Gilbert’s syndrome, biliary obstruction leads to a substantial increase in diarrhea and other side effects. Treatment with irinotecan is not recommended if you have this disorder.

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