Drug therapy options for patients with irritable bowel syndrome

Existing pharmacotherapeutic options for the treatment of patients with irr itable bowel syndrome (IBS) are limited in treating the multiple symptoms a ssociated with the disorder. There is much interest in the use of serotonin agents as new therapeutics. Acting primarily through 5-MT, and 5-MT, recep tors, serotonin elicits changes in motor function and possibly visceral sen sation. Two serotonin agents were developed specifically for IBS: tegaserod , a 5-HT4 receptor partial agonist, and alosetron, a 5-HT3 receptor antagon ist (which is no longer available). Phase III clinical trial data show that during a 12-week treatment period with tegaserod, IBS patients with abdomi nal pain and discomfort, bloating, and constipation experienced significant global relief tie, improvement in overall wellbeing, abdominal pain, and b owel habit) compared with placebo. Improvement in bowel movement frequency and consistency was achieved and pain was relieved by 1 week. During 12 wee ks of treatment, alosetron was shown to elicit significant relief of abdomi nal pain and discomfort compared with placebo or mebeverine in female IBS p atients with diarrhea, Alosetron slowed colonic transit and treatment effic acy was apparent after a week of treatment. Another 5-MT, receptor agonist, prucalopride, which is being developed for chronic constipation, accelerat es colonic transit and increases stool frequency. Therefore, this agent may be of benefit in]BS patients with constipation.