Constipation

Key messages

Clinical practice guidelines from the EAPC are as follows: [1]

  • Constipation in palliative care is fundamentally defined by the patient
  • If the patient complains of constipation or defecates less than three times per week, assessment of bowel habits is warranted
  • A thorough patient history and physical examination are essential
  • A checklist of key facts should be used to assess causative factors and impact of constipation – this assessment should be continuous throughout the patient’s care
  • If malignant intestinal obstruction is suspected, this should be investigated by radiology
  • Preventative measures such as ensuring privacy and comfort, encouraging activity and increasing fluid intake should be ongoing during the patient’s care
  • Rectal intervention should be avoided where possible, but may be necessary where oral medication has been unsuccessful in reestablishing a regular bowel pattern
  • Generally, a combination of a softener (e.g., polyethylene glycol and electrolytes or lactulose) and a stimulant (e.g., senna or sodium picosulphate) laxative is recommended.

Prophylactic co-prescribing of regular laxatives along with regular opioids is identified as best practice. [1-3]

In palliative care patients there is a limit to the potential for prevention and management of constipation by dietary, lifestyle or preventive strategies, and these should not be solely relied upon. [1]

Background

Constipation has been defined as “the passage of small, hard faeces infrequently and with difficulty. Individuals vary in the weight they give to the different components of this definition when assessing their own constipation and may introduce other factors, such as pain and discomfort when defecating, flatulence, bloating or a sensation of incomplete evacuation.” [1] Constipation is a frequent complaint in the general community, and more common in palliative care patients. [4-5] Chronic constipation is one of the commonest side effects of opioids, and occurs in 40 – 70% of patients treated for cancer pain with oral morphine. [6] However other causes of constipation should also be sought and addressed. [4]

An assessment of constipation in the palliative context needs to address opioid induced bowel dysfunction. Other possible contributing factors include:
  • Medications – 5-HT3 antagonists, anticholinergics, iron, some antihypertensives
  • Decreased oral intake, dehydration, alterations in diet
  • Metabolic abnormalities (eg. hypercalcaemia, uraemia, hypothyroidism, hypokalaemia, diabetes)
  • Decreased mobility, weakness, difficulty accessing toilet facilities
  • Bowel obstruction
  • Neurological disorder or damage, eg, due to spinal cord lesion
  • Autonomic neuropathy
  • Depression
  • Terminal phase.

Despite the prevalence of constipation in palliative care patients, it is underdiagnosed and undertreated. [5] Examination of the patient should include a focused rectal examination, including assessment of the pelvic floor and anorectal structures.  Abdominal radiology may be needed to exclude obstruction, but is not required to make a diagnosis. [1]

As well as addressing and modifying any possible causes of constipation, laxatives are usually required. The evidence base supporting the choice of any specific laxative is not strong, either for the general population, [7] or specifically in a palliative care population. [1,8] However, general recommendations for prevention and treatment of constipation in palliative care patients have been made based on expert opinion, and these suggest the combination of a stimulant and a softening agent is usually required. [1] 

Rectal interventions may also be necessary when impaction has occurred, when there is a neuropathic cause for the problem, or when there is a myopathy. This needs to be assessed on the basis of the individual. 

Active research areas / controversies

  • One of the difficulties in researching constipation is the lack of a consensus definition. The EAPC definition relies on the patient’s own subjective assessment of whether or not they are constipated, rather than on frequency of defecation. [1] There are considerable differences between individuals, which make it difficult to propose a general description of normal and abnormal bowel habits. [4] As a result, research on the prevalence of constipation and on the outcomes of treatment is difficult to interpret.
  • There is some evidence to suggest that fentanyl may cause less constipation than other opioids. [6,9]
  • Clinical studies of new drugs for the management of opioid induced bowel dysfunction are ongoing. Several novel opioid antagonists which have only local effects on the gastrointestinal tract, including alvimopan and methylnaltrexone, seem to show promise in clinical trials. [10-12] Methylnaltrexone may have additional benefits in improving gastric emptying, however further research is needed. [13]
  • Other newer potential pharmacological approaches to managing chronic constipation include selective calcium channel agonists (lubipristone) or 5HT3 serotonin receptor agonists (tegaserod).  These agents are not available in Australia and have not yet been studied in the palliative care population. [14]
  • A relationship between deteriorating performance status, opioids, anticholinergic load, proximity of death, and the prescription of laxatives has been suggested. [15]
  

PubMed Searches

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Review Collection
  1. Larkin P, Sykes NP, Centeno C, Ellershaw JE, Elsner F, Eugene B, et al. The management of constipation in palliative care: clinical practice recommendations. Palliat Med. 2008 Oct;22(7):796-807. (155kb pdf)
  2. Palliative Care Expert Group. Therapeutic guidelines: palliative care. Version 3. Melbourne: Therapeutic Guidelines Limited; 2010.
  3. NHS Quality Improvement Scotland (NHS QIS). Best Practice Statement - The management of pain in patients with cancer. Edinburgh: NHS QIS; 2009 Nov.
  4. Davis MP. Cancer constipation: are opioids really the culprit? Support Care Cancer. 2008 May;16(5):427-9. Epub 2008 Jan 15. No Abstract Available.
  5. Droney J, Ross J, Gretton S, Welsh K, Sato H, Riley J. Constipation in cancer patients on morphine. Support Care Cancer. 2008 May;16(5):453-9. Epub 2008 Jan 16.
  6. Cherny N, Ripamonti C, Pereira J, Davis C, Fallon M, McQuay H, et al. Strategies to manage the adverse effects of oral morphine: an evidence-based report. J Clin Oncol. 2001 May 1;19(9):2542-54.
  7. Jones MP, Talley NJ, Nuyts G, Dubois D. Lack of objective evidence of efficacy of laxatives in chronic constipation. Dig Dis Sci. 2002 Oct;47(10):2222-30.
  8. Candy B, Jones L, Larkin PJ, Vickerstaff V, Tookman A, Stone P. Laxatives for the management of constipation in people receiving palliative care. Cochrane Database of Systematic Reviews 2015, Issue 5. Art. No.: CD003448. DOI:10.1002/14651858.CD003448.pub4.
  9. Tassinari D, Sartori S, Tamburini E, Scarpi E, Tombesi P, Santelmo C, et al. Transdermal fentanyl as a front-line approach to moderate-severe pain: a meta-analysis of randomized clinical trials. J Palliat Care. 2009 Autumn;25(3):172-80.
  10. Becker G, Galandi D, Blum HE. Peripherally acting opioid antagonists in the treatment of opiate-related constipation: a systematic review. J Pain Symptom Manage. 2007 Nov;34(5):547-65. Epub 2007 Sep 27.
  11. Thomas J. Opioid-induced bowel dysfunction. J Pain Symptom Manage. 2008 Jan;35(1):103-13. Epub 2007 Nov 5.
  12. McNicol ED, Boyce D, Schumann R, Carr DB. Mu-opioid antagonists for opioid-induced bowel dysfunction. Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD006332. DOI: 10.1002/14651858.CD006332.pub2.
  13. Gatti, A., & Sabato, A. F. (2012). Management of Opioid-Induced Constipation in Cancer Patients: Focus on Methylnaltrexone. Clin Drug Investig, 32(5), 293-301.
  14. Thomas J. Cancer-related constipation. Curr Oncol Rep. 2007 Jul;9(4):278-84.
  15. Clark K, Lam LT, Agar M, Chye R, Currow DC. The impact of opioids, anticholinergic medications and disease progression on the prescription of laxatives in hospitalized palliative care patients: a retrospective analysis. Palliat Med. 2010 Jun;24(4):410-8. Epub 2010 Mar 26.
Last updated 18 January 2017