Constipation From Chemotherapy & Opioids

Constipation is one of the most common problems during cancer treatment, and it is usually one of the most treatable. The National Cancer Institute (NCI) describes constipation as the slow movement of stool (poop) through the large intestine. When stool moves slowly, more water is absorbed out of it, so it becomes harder and drier and comes less often.

NCI lists several reasons people with cancer become constipated:

• Certain cancers. Colon, rectal, and ovarian cancers and brain tumors can block the movement of stool through the bowel or affect the spinal nerves that control it.
• Cancer treatment. Chemotherapy can cause constipation as a side effect.
• Medicines. Opioid pain medicines, antianxiety medicines, antinausea medicines (antiemetics), and diuretics can all slow the bowel.
• Changes in daily life. Moving around less and eating differently than usual both contribute.

Opioids deserve special mention. NCI's page on cancer pain notes that common side effects of pain medicine include constipation, drowsiness, nausea, or vomiting. Unlike drowsiness, constipation from opioids does not usually fade as your body adjusts, so it is often managed from the day the medicine starts rather than after a problem appears.

According to NCI, signs and symptoms include:

• having two or fewer bowel movements in one week
• dry, hard, or lumpy stool
• pain during a bowel movement
• difficulty having a bowel movement
• stomach pain or cramps
• feeling bloated or nauseous

There is no single "normal" pattern. What matters is a change from what is usual for you, which is why NCI suggests keeping a record of your bowel movements.

NCI's practical advice is short and specific:

• Drink plenty of liquids. Drinking 8 cups of water or clear liquids per day can help.
• Try to be active every day. Walking, biking, yoga, or exercises done in a bed or chair all count.
• Eat at the same time each day. A regular schedule helps the bowel keep a rhythm.
• Keep a record of your bowel movements so your team can see what is normal for you and what has changed.
• Ask your doctor about dietary fiber. This one is not automatic. NCI notes that high-fiber foods and fiber supplements can make constipation worse for some people with cancer, so check before you add them.

Use only the products your doctor recommends. NCI describes three types used for constipation: osmotic laxatives, stool softeners, and stimulant laxatives, with examples including polyethylene glycol, docusate, and bisacodyl. Your team will pick based on your treatment, your blood counts, and the other medicines you take.

One safety point from NCI is worth reading twice: do not use suppositories (capsules you insert into your anus) or enemas (liquid medicine that you inject into your anus) unless your doctor recommends them. In some people with cancer, these treatments may lead to bleeding, infection, or other harmful side effects.

NCI's instruction is direct: tell your doctor or nurse if you are having constipation so you can get treatment as soon as possible. Report it if you are having fewer than three bowel movements in one week.

Do not wait it out if things escalate. NCI warns that chronic constipation can lead to fecal impaction or bowel obstruction, two potentially life-threatening conditions that require immediate medical care. Severe stomach pain along with vomiting is a reason to seek care right away rather than to try another laxative at home.

Also contact your doctor or nurse if you are having side effects from your pain medicine. NCI advises calling if new pain appears, if pain is not decreasing with the medicine, or if the medicine is causing problems — constipation included. There is usually a fix, and it rarely requires giving up pain control.

• Which of my medicines are likely to cause constipation, and should I start a bowel regimen now?
• Which laxative or stool softener do you want me to use, at what dose, and how often?
• How many days without a bowel movement should prompt a call to you?
• Should I be adding fiber, or would that make things worse for me?

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• National Cancer Institute — Constipation and Cancer Treatment: https://www.cancer.gov/about-cancer/treatment/side-effects/constipation
• National Cancer Institute — Cancer Pain: https://www.cancer.gov/about-cancer/treatment/side-effects/pain