3 Questions About Defecation Dysfunction and Rectal Sensitivity in Opioid-Related Chronic Constipation

The role of defecation dysfunction and rectal sensitivity in opioid-related chronic constipation is unknown.

To address this, Walter Chan, MD, MPH, director of the Center for Gastrointestinal Motility at Brigham and Women’s Hospital, and colleagues conducted a study that evaluated the relationship between opioid use and rectal sensation, defecatory function, and balloon expulsion with high-resolution anorectal manometry.

Findings from the study indicated that recent opioid use was an independent risk factor for rectal hyposensitivity and defecation dysfunction among patients with chronic constipation. However, the effect may decrease with discontinuation of opioid use.

Gastroenterology Consultant caught up with Dr Chan and the study’s lead author, Nayna Lodhia, MD, about the research. It was recently presented at the American College of Gastroenterology (ACG) 2019 Annual Scientific Meeting and Postgraduate Course.

Gastroenterology Consultant: Why is it important for gastroenterologists to understand the impact of opioids on different variables?

Walter Chan: It is important for a couple of reasons. One is because of the increasing prevalence of opioid use. More and more patients are on narcotic pain medications. We know that narcotic pain medications can have negative effects, or that they can negatively impact gastrointestinal (GI) tract functions. We see a lot of patients with opioid-induced constipation at Brigham and Women’s Hospital. The management of opioid-induced constipation can sometimes be very challenging. A lot of the time, these patients do not respond to the usual laxatives or bowel regimen. We want to know if there are other contributing factors to the constipation that can provide more insight on how to treat these patients that can, in turn, help improve their outcomes.

Nayna Lodhia: The opioid epidemic is affecting many people in this country every single day. I think we need to deal with the medical consequences of patients receiving opioids. A lot of the consequences of opioid use are related to constipation. It is really important for us to understand the pathophysiology of how opioids are affecting patients with constipation in order to treat them appropriately.

GASTRO CON: What prompted you to conduct the study?

WC: Mainly because of the challenge of managing opioid-induced constipation. Traditionally, the management of opioid-induced constipation is focused on increasing colonic transit. We know that for constipation, symptoms may result from both abnormal colonic transit and defecatory dysfunction. So, we asked ourselves, in addition to affecting colonic movement, do opioids also negatively affect anorectal defecation function? We were wondering whether or not narcotics may also impact the anal sphincter muscles that will, in turn, affect the defecation function. This is what prompted us to use high-resolution anorectal manometry in the evaluation.

NL: There is data on how opioids affect different sphincters in different parts of the body; esophagogastric outflow obstruction has been linked to opioid use. However, no one has really looked at whether opioid affects the anal sphincters the same way. We wanted to look at that a little bit closer and see how patients’ pelvic floor function is affected by having previously received opioids a time ago or who received opioids more recently.

GASTRO CON: What is important from the findings that gastroenterologists should be aware of?

NL: The biggest finding was that recent opioid use, which we defined as within the last 3 months, is an independent risk factor for rectal hyposensitivity and dyssynergic defecation. We were able to show this on high-resolution anorectal manometry as an objective measurement in patients who presented with chronic constipation. When patients with constipation present to the office and if they happen to be on opioids or were recently on opioids, we should consider evaluating their defecation function, in addition to treating slow colonic transit alone.

WC: Patients who are on narcotics compared with people who are not on narcotics are more likely to have dyssynergic defecation and also more likely to have a lower sensitivity of the rectum, meaning that it takes a larger volume to trigger a sensation of something in the rectum or the urge to defecate. These findings might explain, or partly explain, why these patients are more likely to be constipated. We found that generally this is associated with more recent use of narcotics. When we compared these patients with patients who had a distant use of narcotics—more than 3 months ago—we did not see the same difference. We think this is important for gastroenterologists for clinical practice because when we treat patients for opioid-induced constipation, we should think more than just about the slow-moving colon. We should also think about whether or not the defecating function is contributing to the symptoms. In addition to prescribing laxatives and the usual medications for constipation, we may also have to think about whether or not to evaluate their defecation function, and potentially use measures like biofeedback therapy to improve their defecation function.

Reference:

Lodhia N, Horton L, Goldin A, Chan WW. Opioid use are independently associated with rectal hyposensitivity and dyssynergic defecation in chronic constipation [abstract 121]. Am J Gastroenterol. 2019;114(2019 ACG Annual Meeting Abstracts):S72-S73. doi:10.14309/01.ajg.0000590016.04310.e7.