Newer Treatments for Irritable Bowel Syndrome

by T. R. Bell

When a painful condition becomes a disease, or in this case a symptom, it changes a number of things for patients, doctors, and researchers. This includes recognition, research, and treatment. This has slowly been happening with irritable bowel syndrome (IBS). One important factor here has been the research and theorizing tied to the 'second brain [1]'. This has lead to research and development of newer treatment.

In lay terms the second brain can be viewed as just that, a brain in the body and in this case it's in the colon. It's similar to the brain in the head as it 'runs' the colon in a way that is semi-independently of the way the brain runs the body. These brains do communicate and one of the ways they communicate is through messengers, such as serotonin (along with up to 30 others). The important thing about serotonin here is that it is a substance which is present in both brains. Just as changes it its level in areas of the brain affects the body so it appears changes in its level in the colon affects the functioning of the colon.

What does it mean to have IBS? It means your body is not working right. What does it mean to have depression or be depressed. Among other things it means you are not working right. Just as the discovery of anti-depressants has led to research and treatment in depression, so potentially could the development of new medications for IBS. If someone is depressed or not working right, they might be given an anti-depressant. Anti-depressants are medications that usually take some time to start working and when they start working it means that in general they have helped make some adjustments in your brain so that your body is once again functioning 'normally' or well.

In simple terms they don't work by pumping fuel into the tank but rather by adjusting the timing so the engine runs well. Timing is only an example here as there are clearly other important aspects of the way the brain runs. The newer medications for IBS work in the same fashion by adjusting the timing in the colon. Just as in the case of depression there are other ways of adjusting the timing so the engine runs right so in the case of IBS there are other ways of 'normalizing' the way the colon works.

Lotronex and zelnorm are the first medications to have reached the marketing stage. Lotronex was released in 2000 and then withdrawn by the manufacturer after some deaths were reported, possibly as a side effect of the medicine. Following an outcry from patients who benefited from lotronex the FDA and it's manufacturer, GlaxoSmithKline, have been conducting a number of meetings to work out a way of re-introducing it, something that has never happened. Lotronex is a 5-HT3 receptor antagonist which means it antagonizes or downplays the receptivity of of the receptor to serotonin, so the receptor takes in less serotonin. It is thought that it reduces visceral sensitivity and modulates diarrhea-predominant urgency.

Zelnorm is a 5-HT4 receptor agonist which means it enhances the receptivity of the receptor to serotonin, so there is less serotonin. It is thought that its basic effects are to reduce visceral sensitivity and alleviate constipation. Zelnorm was scheduled for release in June of 2001, but the FDA has asked the manufacturer, Novartis, to respond to possible complications related to the gall bladder.

These two medications are not necessarily for mild to moderate IBS which distinguishes them from other treatments which are available. There are other possibilities in the works or minds of researchers. It would be wonderful for the many people who have serious IBS if both lotronex and zelnorm were released soon, maybe even before this article sees light. If they aren't this potentially could have further effects on research efforts in this area because of the financial complications involved in the development, regulation, and marketing of treatment in an area not previously thought to be as important to as many people as it is now known to be [3].


[1] Gershom, M. The Enteric Nervous System: A Second Brain, Hospital Practice, 1999.

[2] Farthing M. Baillieres Best Pract Res Clin Gastroenterol 1999 Oct;13(3):461-71

[3] Brickley, P., and Park, P. "FDA Actions, Economy Affect Biotech Industry: Longer Drug Approval Times and Mergers Make for a Bumpy Ride." The Scientist, 15(14): 28, July 9,2001.

© T. R. Bell

T. R. Bell was the founder of the site, Metaphor/Metonym for Health, which features poetry, art by people with chronic illnesses.