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This guidance is largely based on NICE Guideline CG61: Irritable bowel syndrome in adults: diagnosis and management (updated April 2017); it has been developed in collaboration with local specialists.
For diagnosis and referral advice, see the Irritable Bowel Syndrome/Inflammatory Bowel Disease clinical referral guideline.
The British Dietetic Association (BDA) has produced a useful IBS food fact sheet.
Encourage people with IBS to identify and make the most of their leisure time, and to create relaxation time. People with low physical activity levels should be encouraged to increase their physical activity where appropriate.
People with IBS should be advised to:
People with diarrhoea should be advised to avoid sorbitol.
People with wind and bloating may find it helpful to eat oats (cereal/porridge) and linseeds (up to 1 tablespoon per day).
Review the fibre intake of people with IBS, adjusting (usually reducing) it while monitoring the effect on symptoms. People with IBS should be discouraged from eating insoluble fibre (e.g. bran). If an increase in dietary fibre is advised, it should be soluble fibre (e.g. ispaghula powder) or foods high in soluble fibre (e.g. oats).
If symptoms persist, consider referral for a trial low FODMAP diet (specialist dietetic input).
The use of Aloe vera in the treatment of IBS should be discouraged. Aloe vera has been shown to be of no benefit in IBS compared to placebo. Potentially serious adverse effects are associated with aloe vera preparations including an increase in risk of dehydration and electrolyte imbalance when taken with laxative drugs, lowering of potassium levels and possible lowering of blood sugar.
Decisions about drug treatment should be based on the nature and severity of symptoms. The following recommendations assume that the choice of single or combination medication is determined by the predominant symptom(s).
People with IBS should be advised how to adjust their doses of laxative or antimotility agent according to the clinical response. The dose should be titrated according to stool consistency, with the aim of achieving a soft, well-formed stool (corresponding to Bristol Stool Form Scale type 4).
Consider antispasmodics, to be taken when required, alongside dietary and lifestyle advice.
Doses should be adjusted according to response. Avoid lactulose in patients with IBS.
For people who cannot tolerate bulk laxatives or require additional laxatives consider:
Doses should be adjusted according to response.
See section 1.4 Acute diarrhoea
There is evidence suggesting that up to a third of people with a diagnosis of diarrhoea-predominant IBS (IBS-D) have bile acid malabsorption; in patients with significant diarrhoea, despite maximum dose loperamide, GPs may consider the likelihood of bile acid malabsorption diarrhoea. Colestyramine may be used to treat bile acid diarrhoea (unlicensed).
See section 1.9.2 Bile acid sequestrants
Antidepressants are not licensed for use in IBS and should only be used if laxatives, loperamide or antispasmodics have not helped. They may be helpful for the management of functional pain or bloating; Tricyclic antidepressants (TCAs) may also offer an improvement in bowel habit but can induce constipation, therefore their use should be limited to patients with IBS-D.
Amitriptyline (unlicensed indication), should be considered the first choice TCA due to its low acquisition cost
Imipramine (unlicensed indication), less sedating than amitriptyline and should be considered if sedation proves a problem with amitriptyline
Fluoxetine (unlicensed indication), should be considered only if TCAs prove ineffective.
See section 4.3 Antidepressant drugs
If there has been no benefit from dietary and lifestyle advice and pharmacological management after 12 months, consider cognitive behavioural therapy (CBT), which may be available locally or hypnotherapy on a private basis.