Comment

The pharmacological treatment of irritable bowel syndrome (IBS) is currently far from satisfactory and there have been no new drug developments for many years. Recently, there has been a surge of interest in serotonin and the gut with particular emphasis, where IBS is concerned, on 5-HT₃ and 5-HT₄ receptors. A number of agonists and antagonists of these receptors are now under investigation and alosetron (a 5-HT₃ antagonist) was the first to reach the market in the USA.

In the study reported here which was confined to women, alosetron was found to be significantly superior to placebo in providing “adequate relief of pain/discomfort” in patients with diarrhoea and improving bowel function in patients with both diarrhoea and an alternating bowel habit. A particularly noteworthy feature was that the advantage of alosetron was promptly lost when treatment was stopped, suggesting a real effect. The main side effect of treatment was constipation but one case of ischaemic colitis was also reported.

IBS is notorious for its disparate symptomatology1 and the varying importance that patients place on a particular symptom.2 Thus defining a primary outcome measure for trials is fraught with difficulties, an issue which has recently been addressed by the Rome II Consensus Conference.3 It was suggested that a global outcome measure that integrates the key symptoms is probably the most preferable. Thus the “adequate relief of pain/discomfort” used in this study does not quite meet this standard but this trial was designed before the publication of Rome II.

Clinical trials in …