The goal of opioid treatment is to relieve pain and discomfort, but one side effect of the drugs can replace that pain with another problem—opioid induced constipation (OIC). This constipation is more than just a minor inconvenience, says Gregory L. Holmquist, PharmD, CPE, a pain and palliative care specialist. This constipation sometimes becomes so severe that it leads to fecal impaction, which can be life-threatening, according to the National Cancer Institute.1  If untreated, it can lead to colonic necrosis, a dangerous condition that may require surgeons to remove the damaged section of colon, according to Dr. Holmquist. And a significant number of patients taking opioids have constipation even after they take measures to combat it.

Below Dr. Holmquist discusses how to assess patients for OIC, how to prevent the condition and how to manage it.

When treating opioid induced constipation, the first line therapy I recommend is:


In a healthy population, the average frequency of bowel movements ranges from three times a day to three times a week. Based on a patient’s perspective of what is “normal,” he or she may report being constipated, without necessarily meeting the criteria for constipation. How are these patients best managed?

One of the keys to proper treatment is to avoid focusing on the frequency of stools, which can be highly variable among individuals, and instead to ask more detailed questions about stool quality and comfort.

We’ve done a really good job talking about pain with patients. We need to do the same with regard to the issue of constipation. Ask:

  • What’s the consistency?
  • Is it different than in the past?

For example, if a patient is having the same number of stools as he or she typically does, but the stools that are hard as a rock and that the patient is on and off the toilet all day, that indicates a problem. Also, ask if stools have changed over time. If the patient used to have two normal bowel movements twice a week, and now those movements are abnormal in terms of consistency, it can take away from the patient’s quality of life. Constipation can lead to hemorrhoids and anal fissures. In some patients, the bowels become the overwhelming focus of their lives. They are taking pain medication to increase comfort, but instead the discomfort shifts elsewhere.

How does OIC differ from other types of constipation?

The mechanism that causes OIC is different from that of traditional constipation for several reasons. First, the medication slows down peristalsis, so solids don’t move efficiently through the digestive tract. Opiates also displace fluid inside the bowel, which makes the stool hard. The drugs also dampen the normal defecation response—the urge to “go.” Opioids can also affect the secretory glands in the bowel, reducing the amount of natural lubricant inside, causing stool to adhere to the bowel wall. This causes the bowel wall to become rigid, and over time the stool can become impacted.