Definition and diagnosis of opioid-induced constipation in adults

Farmer, 2019Farmer, 2018Muller-Lissner, 2017

Opioids affect gastrointestinal function by stimulating opioid receptors (predominantly mu-receptors), which are widespread throughout the enteric nervous system. This leads to changes in sphincter function, and alteration in gut sensitivity, motility and secreto-absorptive function.

Opioid-induced constipation affects up to 87% of patients receiving opioid therapy for cancer pain and 41 to 57% of those receiving opioid therapy for noncancer painFarmer, 2019.

Diagnosis of opioid-induced constipation (based on the 2016 Rome IV criteria) is made if the patient has:

• new or worsening symptoms of constipation when initiating, changing, or increasing opioid therapy that must include 2 or more of the following:
  • straining during more than 25% of defecations
  • lumpy or hard stools during more than 25% of defecations
  • sensation of incomplete evacuation during more than 25% of defecations
  • sensation of anorectal obstruction or blockage during more than 25% of defecations
  • use of manual manoeuvres (eg digital evacuation, support of the pelvic floor) to facilitate more than 25% of defecations
  • fewer than 3 spontaneous bowel movements per week
• loose stools are rarely present without the use of laxativesRome Foundation Inc., 2016.

In general, investigations are not required to diagnose opioid-induced constipation. The need for investigation depends on the severity of the symptoms, the patient’s age, and the presence of clinical features that warrant further investigation (see Clinical features that warrant further investigation of gastrointestinal symptoms).

The degree of opioid-induced constipation depends on a range of factors, including the patient’s comorbidities, the choice of opioid (including the route of administration and dosage), and the patient’s diet and lifestyle.Farmer, 2019