"This systematic review and meta-analysis shows that ispaghula husk, anti-spasmodics (particularly hyoscine), and peppermint oil are all effective treatments for irritable bowel syndrome," the researchers wrote. The author did not distinguish between constipation- and diarrhea-predominant irritable bowel symptoms.
Most of the remedies require no prescription and are widely available, they noted. "But, with the advent of newer more expensive drugs, [they] are often overlooked as potentially effective treatments."
Dr. Ford and colleagues recommended additional, larger trials of all three types of agents to confirm their effectiveness.
"In the interim, current national guidelines for the management of the condition should be updated to include these data."
The findings are in line with a recent review carried out by a committee of the American College of Gastroenterology, which will soon publish treatment recommendations that also highlight the same three classes of agent. (See ACG: New IBS Management Approaches Addressed in Overhauled Guidelines)
Dr. Ford and colleagues analyzed data from 12 controlled studies of different kinds of fiber, 22 trials involving anti-spasmodic agents, and four trials of peppermint oil. The studies totaled more than 2,700 patients
They found that, after pooling data on five trials of insoluble fiber such as wheat bran, it was no better than placebo at relieving irritable bowel symptoms.
But ispaghula husk, a soluble form of fiber, was significantly effective compared with placebo. Dr. Ford and colleagues found a relative risk of persistent symptoms of 0.78 in patients receiving this agent (95% CI 0.63 to 0.96).
On the other hand, when only studies of high quality -- defined as scores of at least four on the Jadad scale -- were considered, the relative risk increased to 0.86 and was no longer statistically significant.
For antispasmodics, the evidence especially favored otilonium (RR 0.55, 95% CI 0.31 to 0.97) and hyoscine (RR 0.63, 95% CI 0.51 to 0.78).
The most effective agent in this analysis was peppermint oil, with a relative risk for persistent symptoms of 0.43 (95% CI 0.32 to 0.59) on the basis of four studies in 392 patients.
In terms of the number of patients needed to treat (NNT) to have one show sustained benefit, peppermint oil was most effective, with an NNT value of 2.5.
NNT values for ispaghula husk and hyoscine were 6 and 3.5, respectively.
"It would seem reasonable for general practitioners who want to begin a trial of antispasmodics to use hyoscine as first line treatment, but to consider other antispasmodics when this strategy fails," Dr. Ford and colleagues said.
The researchers noted that there was considerable heterogeneity among studies, particularly those of antispasmodics and fiber.
In an accompanying editorial, Roger Jones, M.D., of King's College London in England, suggested caution in interpreting the findings of the meta-analysis.
He noted that Dr. Ford and colleagues did not distinguish between constipation- versus diarrhea-predominant or mixed syndromes, nor did they provide detailed information on dosing or patterns of administration.
Moreover, he wrote, "the analysis does not provide guidance on patient selection for particular agents on the basis, for example, of demographic factors, disease subtype, or clinical history, which limits the implementation of the findings."
Dr. Jones added that it may be premature to change national treatment guidelines on the basis of this analysis.
Nevertheless, he said, "the results should reawaken an interest in the pharmacotherapy of irritable bowel syndrome and stimulate further research."
He agreed with the study authors' recommendation of larger, well-designed trials to answer some of the open questions about these therapies.
Más Información: BMJFord A, et al "Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta-analysis" BMJ 2008; DOI: 10.1136/bmj.a2313.
