A Controlled Therapeutic Study of the Irritable-Bowel Syndrome

Treatment of the irritable-bowel syndrome has not been subjected to adequately controlled studies. Diphenylhydantoin has been reported to be effective. Twelve patients were treated for 20 weeks with 300 mg of diphenylhydantoin daily and with placebo in a randomized double-blind crossover study. Six manifestations scored daily were used as assessment criteria. Psychologic tests were performed. No significant differences (p less than 0.05) between diphenylhydantoin and placebo in any of these manifestations were found. There were positive correlations between frequency and severity of pain and disability but not between frequency, and consistence of stools and pain or disability. These manifestations were strikingly consistent for each patient between biweekly periods. Six of seven patients with the most pain had abnormal scores for neuroticism. There appears to be a rationale for dealing with psychologic factors as well as gut pain in the syndrome. This experimental design should be useful for evaluating other agents in this syndrome.