“I’m drinking plenty of fluids and eating fruits and vegetables.” Patients taking opioids need a stimulant laxative — a “push.”  Often we will hear a patient report, “I’m drinking plenty of fluids and taking Colace.”  And yet they are constipated. The mechanism of action for opioids is to block the opioid receptors.  There are opioid receptors in the gut that are, in effect, blocked by the use of opioids. The usual process of stool being formed and the presence of it stimulating peristalsis is blocked. The correct medication for opioid-induced constipation (OIC) is a stimulant laxative.

The likelihood of patients on opioids who will experience constipation is almost absolute. Even 1 or 2 doses of opioids will disrupt the usual bowel pattern.  A good BM regimen starts with the initiation of opioids. Do not wait. Of course, there are exceptions: Someone who is freshly postop from abdominal surgery may not be a candidate for a stimulant laxative. This will be determined by the surgeon, yet should still be addressed. A person on chemo that is causing diarrhea and who is also on opioid therapy may not require a stimulant laxative.  Radiation therapy to the pelvis may eliminate the need for a laxative at least during therapy.

Colace and extra fluids help with “mush” but without the “push” of the stimulant laxative the formed stool will just sit there, and as it does, fluid is absorbed from it so it becomes harder and more difficult to pass. What are the best stimulant laxatives?  Senna and Dulcolax are both readily available over-the-counter stimulant laxatives. Senna is also available in liquid form if needed. Many patients remember the mush-and-push explanation.

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“I’m not taking the opioids because the constipation is so bad.” What a terrible choice to have to make: Do I accept being in pain because I don’t want to be constipated, or do I manage my pain and accept being constipated? Why must it be an either/or question? The reason to take less pain medication is because of less pain. Opioid constipation must be managed from the initiation of opioid therapy. (Repeat this again and again!)

“My usual pattern is,” “I’m not eating very much.” Although knowledge of a patient’s prior bowel management history is important, in the setting of cancer treatment, it is less significant. Chemo, radiation, opioid use, also use of ondansetron (Zofran) and other medications will alter normal bowel pattern. Instead of focusing on what has been the pattern and even what they have used in the past for constipation, we want our patients to focus on what we are striving for. The goal is a soft-formed BM every 1 to 2 days. Soft and formed means a BM that is the consistency of soft serve ice cream (sorry for the analogy if you love soft serve ice cream). Volume of stool will correspond to amount of food intake. But even if not eating, patients should have a small, soft, and formed BM.  Remind patients that the lining of their gut is like their skin and that it is sloughing off cells and continuing to make secretions in their GI tract which is enough to form a small stool.

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Good bowel management should not be a second thought. Each time we assess for pain we must assess bowel function. I tell my patients right from the beginning that whenever I ask them about their pain I will also ask about their bowels. This alerts them to the potential issue, and also communicates and educates them on the importance of good bowel management. Then to add a little humor, I tell them that if we follow a good regimen we won’t need a back-up plan, pun intended.

Ann Brady is a symptom management care coordinator at a cancer center in Pasadena, California.


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