Constipation (cont.)

If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If a primary doctor is not comfortable performing the evaluation or does not have confidence in doing an evaluation, he or she should refer the patient to a gastroenterologist. Gastroenterologists evaluate constipation frequently and are very familiar with the diagnostic testing described previously.

Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation.

Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (for example, fiber) or more appropriate treatments (for example, biofeedback training) should be used?

Additional resources from WebMD Boots UK on Constipation

REFERENCE:

Fauci, Anthony S., et al. Harrison's Principles of Internal Medicine. 17th ed. United States: McGraw-Hill Professional, 2008.

Previous contributing editor: Dennis Lee, MD

Source: MedicineNet.com
http://www.medicinenet.com/constipation/article.htm