Management

75% of patients are helped by explanation and symptomatic relief.

The fibre content of the diet should be gradually increased. Soluble fibre has been shown to be beneficial (1). Soluble fibre such as isphaghula found in some proprietary fibre products may be of benefit in up to 40% of patients. Trials with bran supplements have shown that bran is no better than placebo. More detailed advice about lifestyle and diet is provided in the linked item.

Drug therapy is directed towards symptomatic relief:

• antispasmodics especially mebeverine hydrochloride, have long usage and their anti-muscarinic actions may relieve pain by moderating smooth-muscle contractions (2).
• peppermint oil (Colpermin, Mintec) 0.2-0.4ml tds 30 minutes before meals may be of benefit with colonic spasm and symptoms of bloating
• anticholinergic effect of a tricyclic antidepressant may be of help - there is evidence that antidepressants seem effective for patients with IBS (4)
• bulk-forming agents for constipation; occasionally constipation-predominant IBS may also require treatment with a laxative
• drugs such as loperamide may be of benefit for diarrhoea - predominant IBS once other pathology has been excluded
• hypnotherapy - a small randomised controlled trial has shown that hypnotherapy can be of benefit in the treatment of symptoms of IBS
• cognitive behaviour therapy - this may be effective (4)

An exclusion diet may be of benefit, e.g. exclusion from diet of wheat flour, dairy produce, tea, coffee, citrus fruits, nuts, chocolate, and food colourings and additives.

With respect to trial evidence

• smooth muscle relaxants are effective for relieving abdominal pain, and loperamide is effective for reducing diarrhoea (5)
• a more recent review also concluded that smooth muscle relaxants (antispasmodics) are effective in IBS (6). Also fibre and peppermint oil are all effective for reducing IBS symptoms and abdominal pain (6)

Note that there is trial evidence that the commercially available herbal preparation STW 5 and its research preparation STW 5-II are both effective in alleviating irritable bowel syndrome symptoms (7).

Notes:

• NICE suggest (8):
  • laxatives should be considered for the treatment of constipation in people with IBS, but people should be discouraged from taking lactulose
  • consider linaclotide for people with IBS only if:
    • optimal or maximum tolerated doses of previous laxatives from different classes have not helped
    • and they have had constipation for at least 12 months
    • follow up people taking linaclotide after 3 months
  • loperamide should be the first choice of antimotility agent for diarrhoea in people with IBS
  • tricyclic antidepressants (TCAs) as second-line treatment for people with IBS if laxatives, loperamide or antispasmodics have not helped
    • treatment should be started at a low dose (5-10 mg equivalent of amitriptyline), which should be taken once at night and reviewed regularly. The dose may be increased, but does not usually need to exceed 30 mg
  • selective serotonin reuptake inhibitors (SSRIs) should be considered for people with IBS only if TCAs have been shown to be ineffective
    • healthcare professionals should take into account the possible side effects when prescribing TCAs or SSRIs. After prescribing either of these drugs for the first time at low doses for the treatment of pain or discomfort in IBS, the person should be followed up after 4 weeks and then at 6-12 monthly intervals thereafter

Reference:

• (1) Bijkerk CJ et al (2004). Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome. Aliment Pharmacol Ther;19:245-51.
• (2) Prescribers' Journal (1997);37(4): 199-205
• (3) Whorwell PJ et al (1994). Controlled trial of hypnotherapy in the treatment of severe refractory irritable bowel syndrome. Lancet; 2: 1232-3.
• (4) Raine R et al (2002). Systematic review of mental health interventions for patients with common somatic symptoms: can research evidence from secondary care be extrapolated to primary care? BMJ; 325: 1082-5.
• (5) Evidence-Based Medicine (2001); 6 (1): 20.
• (6) Ford AC et al.Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta-analysis BMJ. 2008 Nov 13;337:a2313. doi: 10.1136/bmj.a2313.
• (7) Madisch A et al. Treatment of irritable bowel syndrome with herbal preparations: results of a double-blind, randomized, placebo-controlled, multi-centre trial. Aliment Phrmacol Ther 2004;19:271-9.
• (8) NICE (April 2017).Irritable bowel syndrome in adults - diagnosis and management of irritable bowel syndrome in primary care.