Irritable Bowel Syndrome Remains a Difficult Condition to Manage

Nicholas J. Talley, MD, PhD

In This Article


Many different classes of antispasmodic agents are available, with some of these acting directly on intestinal smooth muscle and others having anticholinergic or antimuscarinic actions.[1,2] In the United States, only the antispasmodics dicyclomine and hyoscyamine are available for IBS.[3] A meta-analysis of antispasmodic agents by Poynard and coauthors[20] reported that this drug class did improve global symptoms of IBS and that outcomes with antispasmodics were superior to those with placebo. Use of antispasmodics also provided better pain relief than placebo but did not improve symptoms of abdominal bloating or constipation.[20] Many of these trials had methodologic limitations.[3] Only 3 randomized controlled trials of antispasmodics fulfilled entry criteria for the systematic review by the ACG Task Force ( Table 2 ).[3,16,21,22] Only one of the studies showed any statistically significant benefit in terms of global IBS symptoms compared with placebo[22]; two other studies demonstrated no significant differences.[16,21]

Unfortunately, anticholinergic agents have a number of adverse effects, including visual disturbances, urinary retention, and aggravation of constipation, that potentially limit their use. Some patients anecdotally do seem to benefit from these drugs, particularly if they experience postprandial abdominal pain and take the drug before meals as a prophylactic treatment of the pain.[1] However, the evidence base for this class of agents in IBS remains limited, and for the drugs currently available in the United States, no convincing data on efficacy are available.[3]


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