Dr David Moore
Consultant Pain Specialist & Anaesthetist
Beaumont Hospital & Bon Secours Hospital Dublin
Constipation from pain-relieving opioid use is common, yet more must be done to encourage patients to discuss this common, painful condition.
The ordinary, or functional constipation that most of us are familiar with is usually the result of poor intake of fibre in the diet, dehydration, physical inactivity and aging.1 These factors can all result in the gut contracting more slowly than it would normally do.
Ordinary constipation is said to occur when people are passing less than three stools per week.1 These stools are firm, lumpy and hard to pass.
When opioids are taken for pain, they impact on pain receptors in the spine, but also on other receptors in the body, including in the gut. Opioid-induced constipation results when opioid receptors in the gut are activated. That results in abnormal motions in the gut and the disruption of normal, involuntary, peristaltic motions there.2
This means that waste is not processed along the gut as it should be, but instead, is being passed back and forth.
These effects continue for as long as a patient is taking opioids3 and can lead to severe bloating, a painful bowel, flatulence, inability to pass stools, diarrhoea, nausea, vomiting and lethargy.4 All of which can have impact on your quality of life.
Constipation is common among those prescribed opioids for pain relief, but many patients may be too embarrassed to discuss these symptoms.
In the first instance, a doctor may prescribe a common laxative to determine whether the cause of constipation is the use of opioids.
If the laxative doesn’t work, the doctor may then prescribe a Peripherally Acting μ-Opioid Receptor Antagonist (PAMORA).
The PAMORAs are a novel class of drugs designed to displace the opioid from receptors in the gut, allowing the normal gut function to resume.5
At the same time, the PAMORAs do not displace the opioid from the pain receptors, and so do not interfere with patient pain relief.6
Talking to patients about opioid constipation
Constipation is common among those prescribed opioids for pain relief,6 but many patients may be too embarrassed to discuss these symptoms.
Similarly, doctors who are running busy pain clinics may not do enough to encourage patients to discuss their constipation difficulties.
There is a danger that patients may be unwilling to talk about their constipation for fear their pain-relieving medication will be stopped.
It is important that doctors and nurses, and other pain specialists ask people who are taking opioids whether they suffer from constipation.
Doctors need find ways of letting patients know that it is okay to discuss this important issue which can affect every aspect of their quality of life from work, to sleep, to mood levels and sex life.7
This article was commissioned and funded by Kyowa Kirin
 Relief from Constipation. National Clinical Programme for Palliative Care, HSE. Available at: https:// www.mater.ie/services/palliative-care/relief-constipation.pdf Last accessed: September 2021
 Brock C et al. Opioid-induced bowel dysfunction: pathophysiology and management. Drugs. 2012 Oct 1;72(14):1847-65. 10.2165/11634970-000000000-00000.
 Treatment of Opioid-Induced Constipation: The Hard Facts. Available at: https://www.drugs.com/slideshow/treatment-of-opioid-induced-constipation-the-hard-facts-1283 Last accessed: September 2021
 Drewes AM et al. Definition, diagnosis and treatment strategies for opioid-induced bowel dysfunction-Recommendations of the Nordic Working Group. Scand J Pain. 2016 Apr;11:111-122. 10.1016/j.sjpain.2015.12.005.
 Pergolizzi JV Jr et al. The Use of Peripheral -Opioid Receptor Antagonists (PAMORA) in the Management of Opioid-Induced Constipation: An Update on Their Efficacy and Safety. Drug Des Devel Ther. 2020;14:1009-1025. 10.2147/DDDT.S221278
 Kalso E et al. Opioids in chronic non-cancer pain: systematic review of efficacy and safety. Pain. 2004 Dec;112(3):372-380. 10.1016/j.pain.2004.09.019.
 Bell T et al. Opioid-induced constipation negatively impacts pain management, productivity, and health-related quality of life: findings from the National Health and Wellness Survey. J Opioid Manag. 2009 May-Jun;5(3):137-44. 10.5055/jom.2009.0014.