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Palliative care - constipation

SNOMED: 389082000942 words•Updated 03/03/2026
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Exam Tips

  • In palliative OSCEs, prescribe a stimulant laxative at the same time as a new opioid and state a bowel target of every 1-3 days.
  • If no stool for >3 days or red flags (vomiting, absent flatus, colicky pain, distension), actively exclude obstruction before escalating laxatives.
  • Overflow diarrhoea in a frail immobile patient is often faecal impaction until proven otherwise.
  • Mention rectal exam safety caveat: avoid when chemotherapy-related immunosuppression risk, thrombocytopenia, or significant anal/rectal disease is present.
  • State key drug safety points: co-danthramer is palliative-restricted; methylnaltrexone is contraindicated in suspected bowel obstruction.
  • Visual learning aid: see textbook figures on opioid effects on gut motility and bowel obstruction patterns (e. g, Oxford Textbook of Palliative Medicine diagrams).

Definition

Constipation in palliative care is a subjective but clinically important syndrome of unsatisfactory defecation, due to infrequent stool passage, difficult passage, or persistent feeling of incomplete evacuation. In advanced illness, stool consistency may be hard and dry but can also be normal or soft when the main problem is impaired colonic propulsion (for example opioid-related gut dysmotility).

Pathophysiology

In palliative patients, constipation is usually multifactorial: reduced oral intake and dehydration increase colonic water reabsorption, immobility weakens abdominal/pelvic expulsive effort, and pain or poor toileting conditions suppress defecation. Opioids are a key mechanism, acting at enteric mu-opioid receptors to reduce propulsive peristalsis, increase segmental tone, delay transit, reduce intestinal secretion, and increase anal sphincter tone, causing difficult evacuation. Cancer-related factors (mechanical obstruction, pelvic/lumbosacral neural infiltration, autonomic neuropathy, hypercalcaemia) and comorbid bowel/pelvic floor disease further impair transit or outlet emptying, progressing in severe cases to faecal loading and impaction (most often rectal).

Risk Factors

  • Opioid therapy (very common in advanced cancer pain management)
  • Antimuscarinic/constipating drugs: cyclizine, hyoscine, phenothiazines, tricyclic antidepressants, some antiepileptics, antiparkinsonian drugs
  • Other constipating medicines: calcium/aluminium antacids, iron, diuretics, antihypertensives, ondansetron (5-HT3 antagonist), vinca alkaloids, platinum chemotherapy
  • Poor intake, low fibre intake, dehydration
  • Inactivity, weakness, dyspnoea limiting straining
  • Confusion, depression, cognitive impairment
  • Unfamiliar toilet environment, lack of privacy, bedpan use
  • Direct cancer effects: bowel wall tumour, extrinsic compression, spinal/pelvic neural compression, hypercalcaemia, painful defecation
  • Concurrent disease: diverticular disease, IBD, IBS, hypothyroidism, diabetes, hypokalaemia, rectocele/prolapse, anal fissure/stenosis, neurological disease or spinal cord damage

Clinical Features

Symptoms

  • Hard, uncomfortable, difficult-to-pass stools
  • Reduced stool frequency versus usual pattern; no bowel motion for more than 3 days is a treatment trigger in advanced disease
  • Sensation of incomplete evacuation
  • Straining, ineffective emptying, need for manual manoeuvres
  • Bloating, colicky abdominal pain, abdominal distension, flatulence
  • Anorexia, nausea, vomiting, malaise, halitosis
  • Overflow faecal incontinence/soiling (paradoxical loose stool)
  • Urinary frequency, retention, catheter blockage symptoms
  • Agitation or confusion (especially older patients or those with brain impairment)

Signs

  • Palpable faecal masses abdominally or peri-anally
  • Digital rectal/stoma examination evidence of faecal loading or impaction (if safe to examine)
  • Large infrequent stools (e. g. every 7-10 days) or small frequent stools with incomplete emptying
  • Abdominal distension with tenderness but no peritonism in uncomplicated constipation
  • Possible bowel obstruction signs: absent flatus, colicky pain, distension, vomiting (may be faeculent), tinkling bowel sounds early then reduced/absent late
  • Rectal bleeding or prolapse in complicated cases

Investigations

Focused history and bowel chart:Reduced bowel frequency, difficult stool passage, incomplete evacuation, severity/impact, prior response to laxatives, and contributors (drugs, fluids, mobility, toileting barriers)
Abdominal examination:Distension, palpable faecal loading, or signs concerning for obstruction
Digital rectal examination (when appropriate):Rectal loading/impaction in most cases of faecal impaction; avoid if chemotherapy-related neutropenia risk, thrombocytopenia, or significant anal/rectal pathology
Blood tests: U&E, calcium, thyroid function:May identify reversible contributors such as dehydration/renal dysfunction, hypercalcaemia, or hypothyroidism
Imaging if obstruction suspected (e. g. CT abdomen/pelvis in acute setting):Transition point, tumour compression, or other mechanical cause requiring urgent specialist input

Management

Lifestyle Modifications

  • Set a bowel goal: comfortable bowel movement every 1-3 days without straining
  • Optimise hydration and diet as tolerated by disease stage and appetite
  • Encourage mobility/positioning and toileting privacy; reduce bedpan dependence where possible
  • Address reversible contributors: pain on defecation (fissure/haemorrhoids), dehydration, environmental barriers, constipating co-medication

Pharmacological Treatment

Prophylaxis when starting opioids (first-line stimulant)

  • Senna 15 mg at night initially if not constipated; if no bowel movement after 24-48 hours increase to 15 mg twice daily
  • If already constipated: senna 15 mg twice daily, then 22.5 mg twice daily after 24-48 hours if needed; can add daytime dose and titrate up to 30 mg three times daily (max in palliative titration)

Start laxative at first opioid prescription rather than waiting for symptoms. Titrate to effect while monitoring colic and diarrhoea.

Osmotic adjuncts

  • Lactulose 15-45 mL daily in divided doses, then maintenance 15-30 mL daily
  • Macrogol oral powder 1-3 sachets daily (higher short courses may be used for impaction per product protocol)

Useful with stimulant laxatives, especially when stools are hard/dry. In renal failure, guideline-based palliative options include senna plus lactulose.

Dantron-containing laxatives (specialist palliative use)

  • Co-danthramer (dose varies by formulation and patient response)

Reserved for terminally ill patients in UK practice due dantron safety concerns; may cause perianal irritation and urine discoloration. Avoid routine use outside palliative indication.

Rectal therapy for faecal loading/impaction

  • Glycerol suppository 4 g PR when stool is low and hard
  • Bisacodyl suppository 10 mg PR
  • Phosphate enema 1 unit PR (if not contraindicated)

Treat impaction before escalating oral regimens alone. Use caution in frailty, mucosal disease, and electrolyte disturbance risk.

Opioid-induced constipation refractory to laxatives (specialist)

  • Methylnaltrexone 8 mg SC if 38-<62 kg, 12 mg SC if 62-114 kg, every other day as needed

Consider only after excluding bowel obstruction. Contraindicated in known/suspected GI obstruction; monitor for severe abdominal pain/diarrhoea.

Surgical / Interventional

  • Urgent surgical/oncology/palliative multidisciplinary review if mechanical bowel obstruction is suspected
  • Selected cases may need endoscopic stenting, decompressive procedures, or operative intervention depending on goals of care and performance status
  • Manual disimpaction may be required for severe rectal impaction when less invasive measures fail

Complications

  • Faecal impaction and rectal dysfunction (loss of rectal sensory/motor function)
  • Overflow faecal incontinence (pseudo-diarrhoea)
  • Bowel obstruction
  • Abdominal pain and distension
  • Urinary retention and urinary tract infection
  • Agitation and confusion/delirium exacerbation
  • Rectal bleeding and rectal prolapse

Prognosis

Constipation is highly prevalent in advanced cancer (commonly reported around 40-90%) and often recurs while opioid or other causative factors persist. Prognosis is usually good for symptom control with proactive prophylaxis and early titration, but refractory constipation or obstruction can significantly worsen comfort, delirium risk, and quality of life near end of life.

Sources & References

💊BNF Drug References(27)

✅NICE Guidelines(1)

📖Textbook References(6)

  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 826)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 794)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 829)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 826)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 826)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1195, 1196)[context]

Sources

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