Constipation in Adults

Overview

This updated summary of the NICE Clinical Knowledge Summary (CKS) on constipation covers diagnosis, management, and prescribing. Refer to the full CKS topic for a complete set of recommendations, including background information, recommendations on managing constipation in pregnancy and breastfeeding, and explanation of the specialist investigations and management that are available.

Reflecting on your Learnings

Reflection is important for continuous learning and development, and a critical part of the revalidation process for UK healthcare professionals. Click here to access the Guidelines Reflection Record.

What Are the Secondary Causes?

Possible secondary causes of constipation include:

• Medications:
  • Aluminium-containing antacids; iron or calcium supplements.
  • Analgesics, such as opiates (up to 80% of patients, even with concomitant use of laxatives) and nonsteroidal anti-inflammatory drugs (NSAIDs).
  • Antimuscarinics, such as procyclidine and oxybutynin.
  • Antidepressants, such as tricyclic antidepressants.
  • Antipsychotics, such as amisulpride, clozapine, or quetiapine.
  • Antiepileptic drugs, such as carbamazepine, gabapentin, oxcarbazepine, pregabalin, or phenytoin.
  • Antihistamines, such as hydroxyzine.
  • Antispasmodics, such as dicycloverine or hyoscine.
  • Calcium-channel blockers, such as verapamil.
  • Diuretics, such as furosemide.
• Organic causes:
  • Endocrine and metabolic diseases:
    • Diabetes mellitus (with autonomic neuropathy). See the CKS topics on Diabetes—type 1 and Diabetes—type 2 for more information.
    • Hypercalcaemia and hyperparathyroidism. See the CKS topic on Hypercalcaemia for more information.
    • Hypermagnesaemia.
    • Hypokalaemia.
    • Hypothyroidism. See the CKS topic on Hypothyroidism for more information.
    • Uraemia.
  • Myopathic conditions:
    • Amyloidosis.
    • Myotonic dystrophy.
    • Scleroderma.
  • Neurological conditions:
    • Autonomic neuropathy.
    • Cerebrovascular disease. See the CKS topic on Stroke and TIA for more information.
    • Hirschsprung’s disease. See the CKS topic on Constipation in children for more information.
    • Multiple sclerosis. See the CKS topic on Multiple sclerosis for more information.
    • Parkinson’s disease. See the CKS topic on Parkinson’s disease for more information.
    • Spinal cord injury, tumours.
  • Structural abnormalities:
    • Anal fissures, strictures, haemorrhoids. See the CKS topics on Anal fissure and Haemorrhoids for more information.
    • Colonic strictures (for example following diverticulitis, ischaemia, or surgery). See the CKS topic on Diverticular disease for more information.
    • Inflammatory bowel disease. See the CKS topics on Crohn’s disease and Ulcerative colitis for more information.
    • Obstructive colonic mass lesions (for example due to colorectal cancer). See the CKS topic on Gastrointestinal tract (lower) cancers - recognition and referral for more information.
    • Rectal prolapse or rectocele.
    • Postnatal damage to pelvic floor or third degree tear.
  • Other:
    • Irritable bowel syndrome. See the CKS topic on Irritable bowel syndrome for more information.
    • Slow transit constipation.
    • Pelvic or anal dyssynergia.

When Should I Suspect Constipation?

• Suspect a diagnosis of constipation if an adult presents with defecation which is problematic because of infrequent stools, difficulty passing stools, or a sensation of incomplete emptying or anorectal blockage. 
  • Typically, bowel movements occurring less than three times a week may be regarded as constipation. 
  • There may be daily bowel movements but associated symptoms such as excessive straining. 
  • Additional symptoms may include lower abdominal pain or discomfort, distension, or bloating. 
  • In practice constipation is often defined as passage of stools less frequently than the person's normal pattern. 
• Consider a diagnosis of constipation in the elderly if there are non-specific symptoms, such as: 
  • Confusion or delirium, functional decline. 
  • Nausea or loss of appetite. 
  • Overflow diarrhoea. 
  • Urinary retention. 
• Suspect a diagnosis of faecal loading or impaction if there is history of: 
  • Hard, lumpy stools, which may be large and infrequent (for example passed every 7–10 days), or small and relatively frequent (for example passed every 2–3 days). 
  • Having to use manual methods to extract faeces. 
  • Overflow faecal incontinence, or loose stool. 

How Should I Assess an Adult with Constipation?

If a diagnosis of constipation is suspected, ask about:

• Any red flag symptoms or signs that may suggest a serious underlying cause, such as colorectal cancer. These include a sudden change in bowel habit, rectal bleeding or bloody stools, weight loss, abdominal pain or iron deficiency anaemia. See the CKS topic on Gastrointestinal tract (lower) cancers—recognition and referral for more information. 
• What the person means by 'constipation' and their normal pattern of defecation. 
  • The person's perception of a normal bowel habit may influence the diagnosis of constipation. 
• The duration of constipation, and the frequency and consistency of stools, such as hard/small (pebble-like) or large stools (for example, do they block the toilet); any nocturnal symptoms. 
  • Consider the use of the Bristol Stool Chart to provide an objective record of the person's stool form. 
• Associated symptoms such as rectal discomfort, excessive straining, feeling of incomplete evacuation or blockage, or rectal bleeding; abdominal pain or distension. 
  • Note: pelvic floor dyssynergia may be suggested by straining and a feeling of incomplete evacuation. 
• Associated fever, nausea, vomiting, loss of appetite and/or weight. 
• Associated urinary symptoms, urinary incontinence or retention, dyspareunia. 
• Any family history of colorectal cancer or inflammatory bowel disease. 
• How symptoms affect the person and impact on quality of life and daily functioning. 
• Any self-help measures or drug treatments tried, including over-the-counter medication, and symptom response. 

To assess for any risk factors, ask about:

• The person's diet, including fibre and fluid intake; normal routine or lifestyle; level of activity and mobility. 
• The person's toileting habits, for example feeling hurried or being disturbed when trying to defecate; withholding or ignoring the urge to defecate; access to the toilet at home or work, and level of privacy. 
• Any associated psychological or mental health conditions, such as anxiety, depression, cognitive impairment, or an eating disorder. 
• Any drug treatment or clinical features of an underlying organic cause of secondary constipation, and manage appropriately. 

To assess for faecal loading and/or impaction, ask about:

• A history of faecal incontinence, for example is underwear regularly soiled, excessive wiping, or loose stools. 
• Whether the person has needed to use manual measures to relieve constipation: 
  • A finger having to be inserted into the vagina suggests a rectocele. 
  • A finger in the rectum to push away a flap suggests a rectal ulcer. 
  • Pressure behind the anus may assist defecation if the levator muscles are weak. 
  • Digital rectal evacuation of faeces confirms severe faecal loading and/or impaction. 

Examine the person:

• Assess for signs of weight loss and general nutritional status. 
• Perform an abdominal examination to check for abdominal pain, distension, masses, or a palpable colon (suggesting retained faecal masses). 
• Perform a digital rectal examination, checking for: 
  • Anal fissures, haemorrhoids, skin tags, rectal prolapse, rectocele, skin erythema or excoriation (this may be a sign of faecal leakage). 
  • Resting anal sphincter tone; rectal mass lesions and retained faecal masses, which may also be felt on external peri-anal palpation. Note: a faecal mass can be distinguished from a tumour or cyst, as firm pressure exerted by a finger will typically leave a palpable indentation in hard faeces. 
  • Pelvic floor dysfunction (if appropriate)—while asking the person to 'bear down', there may be paradoxical contraction of the anal sphincter on straining. 
  • Leakage of stool; rectal or anal pain. 

Be aware that no investigations are usually required in an adult with functional constipation where there is no suspected underlying cause.

What Self-management Advice Should I Give?

From age 18 years onwards.

Encourage the person or carer to manage their symptoms by giving advice on:

• Sources of information and support, such as:
  • The NHS patient information leaflets on Constipation and Bowel incontinence.
• Eating a healthy, balanced diet and having regular meals:
  • The person’s diet should contain whole grains, fruits (and their juices) high in sorbitol, and vegetables.
    • Fruits that have a high sorbitol content include apples, apricots, grapes (and raisins), peaches, pears, plums (and prunes), raspberries, and strawberries.
    • The Association of UK Dietitians has useful Food Fact Sheets on Fibre and Fruit and vegetables - how to get five-a-day.
  • Fibre intake should be increased gradually (to minimise flatulence and bloating)—adults should aim to consume 30 g of fibre per day.
    • Advise the person that the beneficial effects of increasing dietary fibre may take several weeks.
    • The type of fibre is also important: psyllium (or isphagula) husk and coarse wheat bran fibres are more beneficial than finely ground wheat bran fibre.
• Public Health England’s booklet The Eatwell Guide has patient information on eating a healthy, balanced diet.
• Drinking an adequate fluid intake, especially if there is a risk of dehydration.
  • The Association of UK Dietitians has a useful Food Fact Sheet on Fluid.
• Increasing activity and exercise levels, if these are below the national recommended levels.
• Helpful toileting routines:
  • Advise on a regular, unhurried toilet routine, giving time to ensure that defecation is complete.
  • Advise on responding immediately to the sensation of needing to defecate.
  • Ensure that people with limited mobility have appropriate help to access the toilet and adequate privacy.
  • Ensure the person has access to supported seating if they are unsteady on the toilet.

How Should I Manage Short-duration Constipation?

For the management of short-duration (less than 3 months) constipation:

• Investigate, exclude and then manage any underlying secondary cause of constipation, if appropriate and possible, and advise the person to reduce or stop any drug treatment that may be causing or contributing to symptoms. This is more likely to be challenging in some elderly people where multimorbidity and polypharmacy are issues.
• Identify if faecal impaction is present as this will need treatment to resolve and may need enemas, suppositores or disimpaction.
• Advise on lifestyle measures, such as increasing dietary fibre, ensuring adequate fluid intake, and activity levels.
• If these measures are ineffective, or symptoms do not respond adequately, offer treatment with oral laxatives using a stepped approach:
  • Offer a bulk-forming laxative first-line, such as ispaghula. Note: it is important for the person to drink an adequate fluid intake.
  • If stools remain hard or difficult to pass, add or switch to an osmotic laxative, such as a macrogol.
    • If a macrogol is ineffective or not tolerated, offer treatment with lactulose second line.
  • If stools are soft but difficult to pass, or there is a sensation of inadequate emptying, add a stimulant laxative.
  • See the section on prescribing information for more information on laxative choices and factors to consider before prescribing different laxatives.
• If the person has opioid-induced constipation:
  • Do not prescribe bulk-forming laxatives.
  • Offer an osmotic laxative and a stimulant laxative.
• Advise the person to gradually reduce and stop laxatives once the person is producing soft, formed stool without straining at least three times per week.
• Arrange to review the person regularly, depending on clinical judgement. See the section on follow-up in primary care for more information.

How Should I Manage Chronic Constipation?

• For the initial management of chronic constipation:
  • Consider, investigate and manage any underlying secondary cause of constipation, and if possible and appropriate advise the person to reduce or stop any drug treatment that may be causing or contributing to symptoms. This is more likely to be challenging in elderly people where multimorbidity and polypharmacy are issues.
  • Identify if faecal loading and/or impaction is present as this will need treatment to resolve and may need enemas, suppositories, or disimpaction.
  • Advise on lifestyle measures, such as increasing dietary fibre, ensuring adequate fluid intake, and activity levels.
• If the person has ongoing symptoms despite these measures, offer drug treatment with oral laxatives using a stepped approach. Adjust the dose, choice, and combination of laxatives used, depending on the person’s symptoms, the desired speed of symptom relief, the response to treatment, and their personal preference.
  • Offer initial treatment with a bulk-forming laxative such as ispaghula. Note: it is important for the person to drink an adequate fluid intake.
  • If stools remain hard or difficult to pass, add or switch to an osmotic laxative, such as a macrogol.
    • If a macrogol is ineffective or not tolerated, offer treatment with lactulose second-line.
  • If stools are soft but difficult to pass or there is a sensation of inadequate emptying, add a stimulant laxative
  • See the section on prescribing information for more information on laxative choices and factors to consider before prescribing different laxatives.
• Consider treatment with prucalopride if at least two laxatives from different classes have been tried at the highest tolerated recommended doses for at least 6 months, and failed to relieve symptoms, where invasive treatment (such as suppositories, enemas, rectal irrigation and/or manual disimpaction) is being considered.
  • The prokinetic prucalopride (a selective, high-affinity, serotonin [5HT4] receptor agonist) stimulates gastrointestinal motility. Offer a prescription for 4 weeks and if there is no symptom response following this trial, reconsider the benefit of continuing treatment.
  • See the section on prescribing information for more information on prucalopride and factors to consider before prescribing it.
• If the person has opioid-induced constipation:
  • Do not prescribe bulk-forming laxatives.
  • Offer an osmotic laxative and a stimulant laxative (or docusate is an alternative which also has stool-softening properties).
• Gradually titrate the laxative dose(s) up or down aiming to produce soft, formed stool without straining at least three times per week.
• Arrange to review the person regularly according to need. See the section on follow-up in primary care for more information.

For recommendations on managing constipation in pregnancy and breastfeeding, refer to the full CKS topic.

How Should I Manage Faecal Loading and/or Impaction?

The aim of management of faecal loading and/or impaction is to achieve complete disimpaction with minimal discomfort. Adjust the dose, choice, and combination of laxatives used, depending on the person's response to treatment and their personal preference.

Following an assessment:

• If there are hard stools, consider prescribing a high dose of an oral macrogol. 
• If there are soft stools, or ongoing hard stools after a few days of treatment with an oral macrogol, consider starting or adding an oral stimulant laxative. 
• If the response to oral laxatives is inadequate or too slow, consider prescribing: 
  • A suppository such as bisacodyl for soft stools; glycerol alone, or glycerol plus bisacodyl for hard stools. 
  • A mini enema such as docusate (softener and weak stimulant) or sodium citrate (osmotic). 
  • Note: enemas may need a district nurse or a carer to administer them. Warn the person that diarrhoea and faecal overflow may occur before disimpaction is complete. 
• If the response to treatment is still inadequate, consider prescribing: 
  • A sodium phosphate or arachis oil retention enema (placed high if the rectum is empty but the colon is full). 
    • For hard stool it can be helpful to give the arachis oil enema overnight before giving a sodium phosphate (large volume) or sodium citrate (small volume) enema the next day. 
    • Enemas may need to be repeated several times to clear hard, impacted faeces. 
• See the section on prescribing information for more information on laxative choices and factors to consider before prescribing different laxatives. 
• Reinforce advice on lifestyle measures such as increasing dietary fibre, fluid intake, and activity levels, to help maintain regular bowel movements and prevent recurrent faecal loading. 
• Consider the need for regular laxative use to maintain regular bowel movements, or the use of intermittent laxatives for episodes of faecal loading. 
  • See the section on managing chronic constipation for more information on regular laxative use. 
• Arrange to review the person every few days to assess the response to treatment, depending on clinical judgement. 

How Should I Follow Up a Person in Primary Care?

Arrange regular follow-up of the person depending on clinical judgement.

• If oral laxatives have been prescribed, advise that: 
  • Laxatives should not be stopped suddenly, and weaning may take several months. The rate of laxative dose reduction should be guided by the frequency and consistency of stools. 
  • Laxative doses should be reduced gradually, for example after 2–4 weeks when regular bowel movements are comfortable, with soft formed stools. 
    • This is to minimize the risk of requiring rescue laxative treatment for recurrent faecal loading and/or impaction. 
    • If a combination of laxatives has been used, reduce and stop one laxative at a time, starting with stimulant laxatives, if possible. Note: it may be necessary to also adjust the dose of other laxatives used to maintain regular bowel movements. 
  • Relapses are common and should be treated early with increased doses of laxatives. 
  • Laxatives may need to be continued long term for people with a medical condition or taking a medication (if it cannot be reduced or stopped) causing secondary constipation. 
• If symptoms are ongoing or refractory to laxative treatment, consider: 
  • Checking blood tests for full blood count, thyroid function tests, HbA1c, and serum electrolytes and calcium, to exclude an underlying cause, and manage appropriately. 
  • Whether a defecatory disorder, such as pelvic floor dyssynergia, may be contributory. 
• Seek specialist advice or arrange referral to a gastroenterologist or colorectal surgeon for specialist investigations and management, depending on clinical judgement, if: 
  • A serious underlying cause such as colorectal cancer is suspected. See the CKS topic on Gastrointestinal tract (lower) cancers - recognition and referral for more information. 
  • An underlying secondary cause of constipation is suspected, which cannot be managed in primary care. 
  • Symptoms persist or recur despite optimal management in primary care. 
• Arrange referral to a local continence service (if available) if there are symptoms of faecal incontinence. 
• Arrange referral to a dietitian if support with dietary changes and increasing fibre content is needed. 

For information on specialist investigations and management, refer to the full CKS topic.

Prescribing Information

Important aspects of prescribing information relevant to primary healthcare are covered in this section specifically for the drugs recommended in this CKS topic. For further information on contraindications, cautions, drug interactions, and adverse effects, see the electronic Medicines Compendium (eMC), or the British National Formulary (BNF).

Choice of Laxatives

The aim of laxatives is to increase stool frequency or ease of stool passage by increasing stool water content (directly by osmotic or intestinal secretory mechanisms) or by accelerating bowel transit.

• Bulk-forming laxatives (containing soluble fibre) act by retaining fluid within the stool and increasing faecal mass, stimulating peristalsis; also have stool-softening properties.
  • Ispaghula husk.
  • Methylcellulose.
  • Sterculia.
• Osmotic laxatives act by increasing the amount of fluid in the large bowel producing distension, which leads to stimulation of peristalsis; lactulose and macrogols also have stool-softening properties.
  • Lactulose.
  • Macrogols (polyethylene glycols).
  • Phosphate and sodium citrate enemas.
• Stimulant laxatives cause peristalsis by stimulating colonic nerves (senna) or colonic and rectal nerves (bisacodyl, sodium picosulfate).
  • Senna—hydrolyzed to the active metabolite by bacterial enzymes in the large bowel.
  • Bisacodyl and sodium picosulfate—hydrolyzed to the same active metabolite. Bisacodyl is hydrolyzed by intestinal enzymes; sodium picosulfate relies on colonic bacteria.
  • Docusate—a surface-wetting agent which reduces the surface tension of the stool, allowing water to penetrate and soften it. Also has a relatively weak stimulant effect.
• Prokinetic laxatives
  • Prucalopride—a selective, high-affinity, serotonin (5HT4) receptor agonist, which stimulates intestinal motility.

Contraindications and Cautions

Do not prescribe laxatives if there is suspected:

• Intestinal obstruction or perforation.
• Paralytic ileus.
• Colonic atony or faecal impaction (bulk-forming laxatives).
• Crohn’s disease or ulcerative colitis.
• Toxic megacolon.
• Severe dehydration (bisacodyl).
• Galactosaemia (lactulose).
• History of hypersensitivity to peanuts (arachis oil enema).

Prescribe laxatives with caution if there is:

• Fluid and electrolyte disturbance—discontinue treatment if there are symptoms of fluid and electrolyte disturbance. Avoid long-term use in pregnancy.
• A history of prolonged use—due to the risk of electrolyte imbalance, such as hypokalaemia. There is a risk of misuse (eg in eating disorders) and rules have changed to limit the number of stimulant laxative medications that can be bought over the counter.
• Cardiovascular disease—do not prescribe more than two sachets of full-strength macrogol compound oral powder in any one hour, and advise the person to discontinue if symptoms of fluid and electrolyte disturbance occur.
• Lactose intolerance (lactulose)—may cause diarrhoea.
• Ischaemic heart disease or arrhythmias (prucalopride).
• Ischaemic colitis (macrogel).

Note: Movicol is considered high in sodium, this should be taken into account for those people on a low salt diet. The absorption of other medicines could be transiently reduced in people taking macrogol products—other medicines should not be taken orally for one hour before, during and for one hour after taking macrogol.

Factors Affecting Choice of Laxative

• The dose, choice, and combination of laxatives used depends on the person’s symptoms, the desired speed of symptom relief, the response to treatment, and their personal preference.

Table 1: Factors Affecting Choice of Laxative

Adverse Effects of Laxatives

Adverse effects of laxatives are generally mild and infrequent, and include:

• Bulk-forming laxatives—flatulence and bloating. Excessive doses or inadequate fluid intake may cause intestinal obstruction.
• Osmotic laxatives—abdominal pain or cramps, bloating, flatulence, nausea and vomiting; less commonly dehydration, especially if inadequate fluid intake.
• Stimulant laxatives—abdominal cramps, diarrhoea, nausea and vomiting. Senna may cause yellowish-brown discolouration of the urine.
• Prucalopride—headache, nausea, diarrhoea, abdominal pain.
• Macrogol laxatives can cause medications taken one hour before, during and one hour after to be flushed out of the gastrointestinal tract unabsorbed which includes contraceptive pills.
• Note: excessive doses of laxatives may cause diarrhoea, which if prolonged, may cause electrolyte disturbances such as hypokalaemia.
• Use of macrogol may result in a potential interactive effect if used with starch-based food thickeners. Macrogol counteracts the thickening effect of starch, resulting in liquefaction of preparations that need to remain thick for people with swallowing problems.