Constipation and Diarrhea: Possible Side Effects from Chemotherapy

While nausea is a well-known side effect of chemotherapy, the lower half of your digestive tract can be disturbed as well, causing constipation or diarrhea.

Constipation is an issue that many patients deal with, though “oftentimes it’s hard to know what’s driving [it],” says Dr. Manojkumar Bupathi, medical oncologist at Rocky Mountain Cancer Centers. “It can be related to the chemotherapy pre-medications that are used; anti-nausea medications can cause constipation, as can pain medications.”

Or “it [may] not necessarily be a side effect of the drugs, but rather of [a patient’s] underlying disease. A lot of times they have something called peritoneal disease, or disease that’s in the lining of the belly. And when that happens, and they’re constipated—or they’re having a lot of diarrhea—[we] want to ensure that there’s no serious problem underlying that’s causing it.” We encourage patients to “make sure they stay on top of it” and keep their doctor apprised.

No matter the cause, there are a lot of options to help relieve gut gridlock. “You can use over-the-counter laxatives, prescription laxatives, herbal supplements, or probiotics,” Dr. Bupathi says. Eating a fiber-rich diet of fresh fruits and veggies and whole grains, and staying well-hydrated are recommended for most people to help keep things moving, though check with your doctor first to make sure there are no high-fiber foods that are off limits.

Some research shows that probiotic-rich foods like yogurt may help promote “good” gut bacteria to help ease constipation, but again touch base with your provider first.

Dealing with Diarrhea

Diarrhea from ovarian cancer chemotherapy may happen less frequently than constipation, but it can occur at some point during your cancer treatment. “As with managing constipation, it’s really important [that we] understand what’s causing it,” Dr. Bupathi says. “Chemotherapy can most certainly do that,” but doctors will want to understand the timing—when it occurs—and how severe it is to help recommend treatment.

There are many options for patients, from “over-the-counter antidiarrheals like Imodium, to oral steroids. There are subcutaneous injections and prescription medications.”

As far as diet goes doctors may recommend what’s called the BRATY diet, made up mostly of Bananas, Rice, Applesauce, Toast, and Yogurt, which
are gentle on the stomach and easy to digest.

To make sure you’re getting enough nutrients try slowing adding in these foods after a few days:

Meat and meat substitutes

• White-meat poultry such as chicken or turkey (with the skin removed)
• Plain baked fish
• Eggs
• Tofu

Vegetables

• Well-cooked carrots, green beans, asparagus tips, and beets
• Baked potatoes without the skin (no fried potatoes)

Because diarrhea can be dehydrating, it’s important to drink plenty of fluids like water, tea, apple juice, or clear broths. Aim to rehydrate with 8-10 glasses of liquid a day, sipping small amounts slowly and more often rather than gulping down a huge glass all at once. Room temperature is recommended.

Reducing Chemotherapy Dose Can Be an Option if Side Effects Persist

“Obviously, we want to make sure that [side effects are] not limiting the functioning ability of our patients,” says Dr. Bupathi. “So sometimes, we may have to come down on the doses of chemotherapy drugs” for better side effects management, “and to maintain their quality of life.”

It is important to reach out to your healthcare provider if any side effects become severe. They have many tools in their arsenal to help you get through your treatment as comfortably as possible.

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