3. Constipation in Adults

Constipation in Adults

This PatientPlus article is written for healthcare professionals so the language may be more technical than the condition leaflets. You may find the abbreviations list helpful.

For children, see separate article Constipation in Childhood.

Chronic constipation is common with a reported prevalence of 14% worldwide, with a significantly higher prevalence in women and people of lower socio-economic status. Symptoms often fluctuate and persistent symptoms over 10 to 20 years affect only 3% of adults.[1] Chronic constipation refers to patients who have had symptoms for more than six months.[2]

Constipation can affect quality of life and may be associated with haemorrhoids and anal fissures, and serious underlying causes, such as colorectal cancer. Constipation may be associated with a modest reduction in survival.[1]

Constipation is a symptom not a diagnosis and means different things to different people. Always ask patients exactly what they mean by the term constipation. There are various formal (and different) definitions of constipation. It is defined as defecation that is unsatisfactory because of infrequent stools (<3 times weekly), difficult stool passage (with straining or discomfort), or seemingly incomplete defecation. Stools are often dry and hard, and may be abnormally large or abnormally small.[3]

Patients may mean that:

  • Faeces are too hard.
  • They do not defecate often enough for 'inner cleanliness'.
  • Defecation hurts.
  • They have diarrhoea.

Taking a careful history helps to determine the possible cause. Always consider the possibility of a serious underlying cause. Particularly enquire whether there are associated 'red flags' such as weight loss or rectal bleeding.

Ask about frequency, nature and consistency of the stool. Is there blood or mucus in/on the stools? Is there diarrhoea alternating with constipation? Has there been a recent change in bowel habit? Ask about diet and drugs.

Always perform a thorough examination of the abdomen, which should include a rectal examination.

Causes of Constipation
Common Causes Low-fibre diet
Inadequate fluid intake or dehydration
Immobility (or lack of exercise)
Irritable bowel syndrome
Old age
Postoperative pain
Hospital environment (lack of privacy, having to use a bedpan)
Anorectal Disease Anal fissure
Anal stricture
Rectal prolapse
Intestinal Obstruction Strictures (eg, Crohn's disease)
Colorectal carcinoma
Pelvic mass (eg, fetus, fibroids)
Diverticulosis (rectal bleeding is a more common presentation)
Congenital abnormalities
Pseudo-obstruction
Metabolic/Endocrine Hypothyroidism
Hypercalcaemia
Hypokalaemia
Porphyria
Lead poisoning
Drugs Opioid analgesics (eg, morphine, codeine)
Anticholinergics (tricyclics, phenothiazines)
Iron
Neuromuscular Spinal or pelvic nerve injury
American Trypanosomiasis, Hirschsprung's disease
Systemic sclerosis
Diabetic neuropathy
Other Causes Chronic laxative abuse (rare - diarrhoea is more common)
Idiopathic slow transit
Idiopathic megarectum/colon
  • Most constipation does not need investigation, especially in young, mildly affected patients.
  • Indications for investigation include:
    • Age >40 years.
    • A recent change in bowel habit.
    • Associated symptoms (weight loss, rectal bleeding, mucous discharge, or tenesmus).
  • Possible investigations include:
    • Blood tests: FBC, U&E, Ca2+, TFTs.
    • Sigmoidoscopy and biopsy of abnormal and normal mucosa.
    • Barium enema if there is suspected colorectal malignancy.
    • Special investigations (eg, transit studies, anorectal physiology) which are occasionally indicated.
  • Treat the cause.
  • Mobilise the patient.
  • Increase fluid intake; increase intake of high-fibre foods (including fruits, vegetables, whole wheat and bran).
  • Consider drugs only if the above measures fail.
  • Try to use drugs for short durations only.

Drug therapy

Drugs for Constipation
Bulk producers:
  • Increase faecal mass, which stimulates peristalsis.
  • They must be taken with plenty of fluid
  • Contra-indications: difficulty in swallowing; intestinal obstruction; colonic atony; faecal impaction.
 Examples:
  • Bran powder 3.5 g 2-3 times/day with food.
  • Ispaghula husk - eg, Fybogel® 3.5 g sachet in water after meals.
  • Methylcellulose - eg, Celevac® 3-6 500 mg tablets/12-hourly with water.
  • Sterculia - eg, Normacol® 7 g sachets/1-2 sachets in water once or twice a day after meals.
Stool softeners:
  • Side-effects can include: anal seepage, lipoid pneumonia, malabsorption of fat-soluble vitamins.
  • Arachis oil enemas lubricate and soften impacted faeces.
  • Liquid paraffin should not be used for a prolonged period.
Stimulants:
  • Increase intestinal motility and should not be used in intestinal obstruction.
  • Prolonged use should be avoided, as it may cause colonic atony and hypokalaemia (but there are no good, long-term follow-up studies).
  • Pure stimulant laxatives are bisacodyl tablets (5-10 mg at night) or suppositories (10 mg in the mornings) and senna (2-4 tablets at night).
  • Docusate sodium and dantron have stimulant and softening actions; however, dantron is associated with colonic and liver tumours in animals - so reserve its use for the very elderly and the terminally ill.
  • Glycerol suppositories act as a rectal stimulant.
  • Sodium picosulfate is useful for rapid bowel evacuation prior to procedures.
Osmotic agents:
  • Retain fluid in the bowel.
  • Lactulose, a semisynthetic disaccharide, produces an osmotic diarrhoea of low faecal pH that discourages growth of ammonia-producing organisms. It is useful in constipation (dose: 15 mL/12-hourly) and hepatic encephalopathy (dose: 30-50 mL/12-hourly).
  • Magnesium salts (eg, magnesium hydroxide and magnesium sulfate) are useful when rapid bowel evacuation is required.
  • Macrogols can be used in the long-term management of chronic constipation.
Enemas and suppositories - useful additional treatment.
  • Sodium phosphate enemas and glycerin suppositories may be useful.
  • Sodium salts (eg, Micolette® and Micralax® enemas) should be avoided, as they may cause sodium and water retention.
  • Phosphate enemas are useful for rapid bowel evacuation prior to procedures.
  • Excessive use of soapy tap water enemas may lead to water intoxication.
Cost
  • Cheap: senna, bran, co-danthrusate, bisacodyl.
  • Moderate: magnesium hydroxide, methylcellulose, ispaghula granules, sterculia.
  • Expensive: lactulose.

Prucalopride[4]

  • Prucalopride is a selective serotonin 5HT4-receptor agonist with prokinetic properties.[5]
  • Prucalopride is recommended as an option for the treatment of chronic constipation only in women for whom treatment with at least two laxatives from different classes, at the highest tolerated recommended doses for at least six months, has failed to provide adequate relief and invasive treatment for constipation is being considered.
  • If treatment with prucalopride is not effective after four weeks, the woman should be re-examined and the benefit of continuing treatment reconsidered.
  • Prucalopride should only be prescribed by a clinician with experience of treating chronic constipation, who has carefully reviewed the woman's previous courses of laxative treatments.
  • Obstructed defecation syndrome (ODS) is characterised by an urge to defecate but an impaired ability to expel the faecal bolus.
  • Symptoms include unsuccessful attempts at faecal evacuation, excessive straining, pain, bleeding after defecation and a sense of incomplete faecal evacuation.
  • Women, especially multiparous women, are more likely than men to present with symptoms of ODS.
  • ODS is often associated with structural defects in the rectum, such as rectocele, internal rectal prolapse and perineal descent.
  • Conservative treatments include diet, biofeedback, laxatives and pelvic floor retraining.
  • Surgery may be considered for patients not responding to conservative treatment or if a structural abnormality is present, Surgical options include stapled transanal prolapsectomy, perineal levatorplasty (STAPL), stapled transanal rectal resection (STARR) and laparoscopic ventral mesh sacrocolporectopexy.
Provide feedback

Further reading & references

  1. Ford AC, Talley NJ; Laxatives for chronic constipation in adults. BMJ. 2012 Oct 1;345:e6168. doi: 10.1136/bmj.e6168.
  2. Lacy BE, Levenick JM, Crowell M; Chronic constipation: new diagnostic and treatment approaches. Therap Adv Gastroenterol. 2012 Jul;5(4):233-47. doi: 10.1177/1756283X12443093.
  3. Constipation, Prodigy (January 2008)
  4. Prucalopride for the treatment of chronic constipation in women, NICE Technology Appraisal Guideline (December 2010)
  5. Liu LW; Chronic constipation: current treatment options. Can J Gastroenterol. 2011 Oct;25 Suppl B:22B-28B.
  6. Stapled transanal rectal resection for obstructed defaecation syndrome, NICE Interventional Procedure Guideline (June 2010)
Original Author: Dr Richard Draper Current Version: Peer Reviewer: Dr John Cox
Last Checked: 28/02/2013 Document ID: 2001  Version: 22 © EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.