Opioid induced constipation (OIC)
Effect of opioids on the gut
| SITE | PHARMACOLOGICAL ACTION | CLINICAL EFFECT |
|---|---|---|
| Stomach | Decreased gastric motility Decreased pyloric tone |
Anorexia Nausea and vomiting |
| Small intestine | Reduced propulsion Increased fluid absorption Decreased pancreatic and biliary secretion |
Delayed absorption of medications Hard, dry stool Delayed digestion |
| Large intestine | Increased non-propulsive contractions Increased fluid absorption Increased anal sphincter tone |
Spasm, abdominal cramps, pain Hard, dry stool Incomplete evacuation |
CNS3
BRAIN AND SPINAL CORD
Clinical Effect:
Provides analgesia
Side Effects:
Sedation
Respiratory depression
Nausea/vomiting
GI TRACT WITH MYENTERIC AND SUBMUCOSAL PLEXUS1,2
Clinical Effect:
Slows GI propulsion
Reduces intestinal secretion
Side Effects:
Constipation
CNS3
BRAIN AND SPINAL CORD
Clinical Effect:
Provides analgesia
Side Effects:
Sedation
Respiratory depression
Nausea/vomiting
GI TRACT WITH MYENTERIC AND SUBMUCOSAL PLEXUS1,2
Clinical Effect:
Slows GI propulsion
Reduces intestinal secretion
Side Effects:
Constipation
DEFINITION OF OIC
- Straining during more than one-fourth (25%) of defecations
- Lumpy or hard stools (BSFS 1-2) more than one-fourth (25%) of defecations
- Sensation of incomplete evacuation more than one-fourth (25%) of defecations
- Sensation of anorectal obstruction/blockage more than one-fourth (25%) of defecations
- Manual manoeuvres to facilitate more than one-fourth (25%) of defecations
- Fewer than 3 spontaneous bowel movements per week
To find out more about OIC and its impact on patients, visit the OIC eLearning module
Differential diagnosis of oic
| OIC5 | FUNCTIONAL CONSTIPATION6 | |
|---|---|---|
| Mechanism | Persistent activation of colonic mu-receptors | Diminished intestinal motility or mechanical, physiologic or congenital inability to propagate the stool out of the rectum |
| Causes | Opioid treatment |
|
| Treatment | Specific blockade of mu-opioid receptor stimulation in the gastrointestinal tract | Dietary changes: increased fluid and fibre intake; exercise; stool softeners; various laxatives |
BSFS = Bristol Stool Form Scale
References: 1. Kurz A. Opioid-induced bowel dysfunction: pathophysiology and potential new therapies. Drugs. 2003;63(7):649-671 2. Nelson A, Camilleri M. Chronic opioid induced constipation in patients with nonmalignant pain: challenges and opportunities. Therapeutic Advances in Gastroenterology. 2015;8(4):206-220. 3. Holzer P. Pharmacology of Opioids and their Effects on Gastrointestinal Function. The American Journal of Gastroenterology Supplements. 2014;2(1):9-16. 4. Simren M, Palsson O, Whitehead W. Update on Rome IV Criteria for Colorectal Disorders: Implications for Clinical Practice. Current Gastroenterology Reports. 2017;19(4). 5. Camilleri M, Drossman D, Becker G, et al. Emerging treatments in neurogastroenterology: a multidisciplinary working group consensus statement on opioid-induced constipation. Neurogastroenterology & Motility. 2014;26(10):1386-1395. 6. Alame A, Bahna H. Evaluation of Constipation. Clinics in Colon and Rectal Surgery. 2012;25(01):005-011.
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