Pharmacologic treatment of the irritable bowel syndrome: a systematic review of randomized, controlled trials

the Cochrane controlled trials registry and a manual search of references from bibliographies of identified articles. Study Selection: Randomized, double-blind, placebo-controlled, parallel, or crossover trials of a pharmacologic intervention for adult patients that reported outcomes of improvement in global or irritable bowel–specific symptoms. Data Extraction: Qualitative and quantitative data reported on study groups, interventions, treatment outcomes, and trial meth-odologic characteristics. Data Synthesis: 70 studies met the inclusion criteria. The most common medication classes were smooth-muscle relaxants (16 trials), bulking agents (13 trials), prokinetic agents (6 trials), psy-chotropic agents (7 trials), and loperamide (4 trials). The strongest evidence for efficacy was shown for smooth-muscle relaxants in patients with abdominal pain as the predominant symptom. Lop