The differences between irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are discussed along with emerging treatments for both conditions. The recent withdrawal of tegaserod (Zelnorm) for the treatment of IBS-c has left many searching for new therapies.
Asking patients who complain of gastrointestinal symptoms whether they suffer from inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS) may be a waste of time. Chances are pretty good they wouldn't understand the differences between the two disorders as confusion abounds when it comes to identification and diagnosis of many of the common GI conditions. Even many healthcare professionals have a hard time keeping the terms, symptoms, and treatments straight. And, if we took the time to look back at our pharmacy therapeutics class notes for the basic definitions, we would find that those have also changed and evolved over the years.
So what is the difference between IBS and IBD? According to the Crohn's & Colitis Foundation of America, IBS affects an estimated 10% to 20% of American adults, mostly women, and symptoms can vary from patient to patient. Typically, abdominal pain and discomfort are often experienced, with changes in bowel function that can be either predominantly diarrhea (IBS-d) or constipation (IBS-c), or even a mixed form (IBS-m), with alternating bouts of the two. IBS is considered a functional disorder, meaning there is some type of GI disturbance, but no sign of abnormality or disease.
Although some of the symptoms of both IBS and IBD can be similar, the one million or so adults in the United States who suffer with ulcerative colitis (UC) or Crohn's disease (CD)-collectively known as IBD-experience destructive inflammation that can lead to permanent damage to the intestine, intestinal bleeding, or the development of fistulas and abscesses.
Out of gas
In April, patients suffering from IBS-c heard the news they would no longer have the option of treatment with the only approved medication for this condition, tegaserod (Zelnorm). Novartis moved to suspend marketing, sales, and distribution of the drug at the request of the FDA after a retrospective analysis of more than 18,000 patients in the clinical trial database revealed an increased risk for cardiovascular events, including myocardial infarction, stroke, and unstable angina pectoris. The incidence was relatively small (0.11%), according to the manufacturer, but significant. Data showed 13 events in a total of 11,614 patients treated with tegaserod compared with one case in 7,031 patients treated with placebo (0.01%). All 13 patients affected also had preexisting cardiovascular disease and/or risk factors.
The drug's removal was surprising and disappointing to many IBS patients loyal to tegaserod, forcing some to seek it on-line or overseas. Many contacted the FDA themselves in an effort to get the drug back on the market. Jeffrey Roberts, founder of the Irritable Bowel Syndrome Self Help and Support Group, said he encouraged his organization's 20,000 members to write to the agency and complain. According to Novartis, an estimated 500,000 people in the country were taking the drug before its removal, leading to $488 million in annual sales.
The FDA said it would hold a public advisory committee meeting to review more safety data and might consider a limited reintroduction if Novartis can identify a select subpopulation of patients in whom the benefits outweigh the risks.
Now that tegaserod is gone, companies are boasting about alternative products that may help treat IBS, such as new entities, antibiotics, and probiotics.