NICE guidance on irritable bowel syndrome

NICE has published guidance on the diagnosis and management of irritable bowel syndrome (IBS) in primary care.

The guideline provides positive diagnostic criteria for patients presenting with symptoms suggestive of IBS, guidance on clinical and cost-effective management of IBS in primary care and clinical indications for referral to IBS services.


  • Consider assessment for IBS if the patient reports having abdominal pain or discomfort, bloating or a change in bowel habit for at least six months.
  • Ask all patients presenting with possible symptoms of IBS if they have any of the following ‘red flag’ indicators and refer to secondary care for further investigation if any are present:
    - unintentional and unexplained weight loss
    - rectal bleeding
    - a family history of bowel or ovarian cancer
    - a change in bowel habit to looser and/or more frequent stools persisting for more than six weeks in a person aged over 60 years.
  • Assess and clinically examine all patients presenting with possible IBS symptoms for the following ‘red flag’ indicators and refer to secondary care for further investigation if any are present:
    - anaemia
    - abdominal masses
    - rectal masses
    - inflammatory markers for inflammatory bowel disease if there is significant concern that symptoms may suggest ovarian cancer, a pelvic examination should also be considered.


  • Consider a diagnosis of IBS only if the patient has abdominal pain or discomfort that is:
    - relieved by defaecation or
    - associated with altered bowel frequency or stool form.
    This should be accompanied by at least two of the following four symptoms:
    - altered stool passage (straining, urgency, incomplete evacuation)
    - abdominal bloating, distension, tension or hardness
    - symptoms made worse by eating
    - passage of mucus

    Other features such as lethargy, nausea, backache and bladder symptoms are common in people with
    IBS, and may be used to support the diagnosis.
  • In patients who meet the iBS diagnostic criteria, perform the following tests to exclude other diagnoses:
    - full blood count
    - erythrocyte sedimentation rate
    - C-reactive protein
    - antibody testing for coeliac disease.


  • Encourage patients with iBS to identify and make the most of their available leisure time and to create
    relaxation time.
  • Assess diet and give general advice: encourage patients to have regular meals and to drink at least eight cups of fluid per day, restricting tea and coffee to three cups a day; advise patients with diarrhoea to avoid sorbitol; advise patients to limit intake of high-fibre food and fresh fruit. Refer to a dietitian if diet considered a major factor in symptoms.
  • Review and adjust (usually reducing) patients’ fibre intake while monitoring the effect on symptoms. Discourage patients from eating insoluble fibre (e.g. bran) and encourage them to eat soluble fibre (e.g. oats) if an increase in dietary fibre is advised.
  • Assess physical activity levels and advise patients to increase their activity where applicable.
  • Discourage the use of aloe vera, acupuncture and reflexology in the treatment of IBS.


  • Consider treatment with antispasmodic agents (taken as required) alongside dietary and lifestyle advice.
  • Consider laxatives for patients with constipation, but discourage the use of lactulose.
  • Offer loperamide as the first choice of antimotility agent in patients with diarrhoea.
  • Advise patients how to adjust their doses of laxative or antimotility agent according to clinical response. The dose should be titrated according to stool consistency, with the aim of achieving a soft, well-formed stool.
  • Consider tricyclic antidepressants (TCAs) as second-line treatment if laxatives, loperamide or antispasmodics have not helped. TCAs are recommended for their analgesic effect. Start treatment at a low dose (5–10mg equivalent of amitriptyline) to be taken once at night and review regularly. The dose may be increased, but does not usually need to exceed 30mg.
  • Consider selective serotonin reuptake inhibitors (SSRIs) only if TCAs have been shown to be ineffective.
  • Patients taking TCAs or SSRIs should be followed up after four weeks and then at six- to 12-monthly
    intervals thereafter.
  • Consider referral for psychological interventions for patients who do not respond to pharmacological treatments after 12 months and who develop a continuing symptom profile (refractory IBS).

The full guideline is available at

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