Diagnosis of Opioid-Induced Constipation

Gerald Sacks, MD: A patient will come in and obviously be on opioids—because that’s what we’re talking about, opioid-induced constipation [OIC]—and I’ll ask them how frequently they go to the bathroom and whether they feel their bathroom activity is a full, successful activity. Meaning, do they feel they’re fully evacuating? I ask if they have bloating, nausea, or vomiting. I ask how often they go to the bathroom, and if their bathroom habits have changed since they’ve been on opioids. In other words, let’s say that they were going to the bathroom and having a bowel movement once a day, and now they’re taking opioids. If they’re going to the bathroom or having a bowel movement once a week, certainly that would be a concern.

The goal of addressing and treating opioid-induced constipation is to have the patient maintain their normal level of bowel function, whatever that happens to be for that patient. For some of my patients, their normal baseline bowel function is that they go to the bathroom once a day. Some patients go 2 to 3 times a day. Some have their normal bowel function—going to the bathroom, having a bowel movement—every other day. What I want to do with these medications and lifestyle changes is to make sure that the patient is maintaining whatever their normal bowel function is for them.

Fariborz Rezai, MD, FCCP, FCCM: With OIC diagnosis, it’s a bit different from other types of constipation. There is the Rome-IV criteria to the Bristol Stool Scale, but those are meant to be more for irritable bowel syndrome and other forms of functional constipation. OIC has to do more with the opioid’s effect on immune receptors in the gut. By blocking those receptors, it causes the gut not to function appropriately: Decreased peristalsis, decreased fluid secretion, and increased fluid absorption. This makes the gut—more so the contents of the gut—drier, and the gut will not move as much because of decreased peristalsis.

With the Rome-IV Criteria, OIC is more of a functional constipation. We look at return abdominal pain at least 1 day a week, lasting 3 months, associated with at least 2 criteria. I won’t go into it. But again, these are useful tools. When using these tools, keep in mind that they don’t apply as much to OIC because they’re more secondary to the opioid effect. The Bristol Stool Scale has more to do with the formation of the feces, and it falls into 7 categories.

The goal of OIC treatment is really to evaluate if your patient is truly constipated. It’s part of the differential diagnosis. Obviously, our patient has to be on opioids. In the ICU [intensive care unit], many patients are on a continuous opioid drip like fentanyl. Most of these patients, if not all, are receiving some type of bowel regimen. Despite having the maximized bowel regimen, these patients are still constipated. They have an abdominal distension and bloating. The nurse will pretty much tell you the patient hasn’t had a bowel movement in a few days. In the hospital or ICU, those are the telltale signs of a patient who may have OIC.

Transcript Edited for Clarity