14/11/08 Fibre, antispasmodics and peppermint oil are all effective therapies for irritable bowel syndrome (IBS) and should become first-line treatments, according to a study on bmj.com.

National guidelines on the management of IBS should be updated in light of this evidence, say the authors.

IBS is characterised by abdominal pain and an irregular bowel habit, and affects between 5% and 20% of the population. Because the exact cause of IBS is unknown it is difficult to treat. A wide range of therapies are currently used including fibre supplements, probiotics, antidepressants, hypnotherapy and laxatives.

Because of a lack of suitable drug treatments, international and national guidelines promote the use of complementary and alternative treatments, including the recently published National Institute of Health and Clinical Excellence (NICE) guidelines on the management of IBS.

Fibre, antispasmodics and peppermint oil are used to treat IBS, but evidence of their effectiveness is unclear because of conflicting conclusions and errors in previous studies.

In an attempt to resolve this uncertainty, Dr Alex Ford and colleagues performed a systematic review and meta-analysis of randomised trials comparing fibre, antispasmodics and peppermint oil with placebo or no treatment in more than 2500 adult patients with IBS..

Fibre, antispasmodics and peppermint oil were all found to be effective treatments for IBS. The number needed to treat to prevent IBS symptoms in one patient was 11 for fibre, 5 for antispasmodics, and 2.5 for peppermint oil. None of the treatments had serious adverse effects.

The researchers analysed 12 studies which compared fibre with placebo or no treatment involving 591 patients. Interestingly, insoluble fibre such as bran was not beneficial, only isphaghula husk (soluble fibre) significantly reduced symptoms.

They identified 22 studies comparing various antispasmodics with placebo in 1778 patients. Hyoscine was the most successful at preventing symptoms of IBS. The authors suggest that hyoscine, which is extracted from the cork wood tree, be used as the first-line antispasmodic therapy in primary care.

Peppermint oil seemed to be the most effective treatment of the three, based on four trials involving 392 patients.

These treatments have been overlooked because of the introduction of newer more expensive drugs which were withdrawn due to lack of efficacy and safety concerns, say the authors. All three treatments have been shown to be potentially effective therapies for IBS and current national and international guidelines need to be revised to include this new evidence, they add.

The results of this study should "reawaken interest in the pharmacotherapy of irritable bowel syndrome and stimulate further research", says Professor Roger Jones from King's College London.

However, he cautions that this new evidence must not detract from the need to make a holistic diagnosis and integrated approach to the treatment of IBS which takes account of the physical, psychological, and social factors involved.