By Harvard Medical International
Another IBS drug has been taken off the market because of serious side effects. Now what?
In March 2007, at the request of the FDA, the pharmaceutical company Novartis agreed to halt the sale of Zelnorm (tegaserod maleate), a drug used in the short-term treatment of irritable bowel syndrome (IBS) when the main symptom is constipation. Zelnorm was approved in 2002 for women with IBS and, later, for men and women under age 65 with chronic constipation. The FDA's request was based on an analysis showing that, compared with a placebo, Zelnorm slightly increased the risk for heart attack, angina, and stroke. But this wasn't the first sign of trouble for the drug. Its label had already been changed, in 2004, to include warnings about serious side effects, including ischemic colitis (lack of blood flow to the intestine).
Zelnorm is the second IBS drug to be recalled. Lotronex (alosetron hydrochloride), approved in early 2000 for women with diarrhoea-predominant IBS, was pulled from the market within nine months, after studies linked it to ischemic colitis and bowel obstruction. Propulsid (cisapride), a heartburn drug often used by IBS sufferers, was also withdrawn that year because of cardiovascular risks.
Ways to manage IBS
For many women, Zelnorm and Lotronex were very effective, and the benefits of these drugs may still outweigh the risks when nothing else works. So the FDA has made Lotronex available again under tight control (www.lotronex.com) and will do the same for Zelnorm.
IBS can cause recurrent bouts of constipation or diarrhoea (or both in alternation), abdominal pain or cramping, gas, and bloating. It's a functional disorder - that is, it hasn't been traced to any underlying disease or structural abnormality - and it doesn't increase a woman's risk for more serious disorders, such as ulcerative colitis or colon cancer. Experts suspect that it develops when faulty nerve signals in the gut and brain somehow disrupt normal muscle activity and sensation in the intestine. There's no cure for IBS, but there are many options for treating it, depending on the predominant symptoms:
Constipation.Bulking agents (bran and fibre supplements such as psyllium or methylcellulose) help move waste through the intestines. However, they can cause gas and bloating, so patients should start slowly and gradually increase their intake. Drinking plenty of fluids is also important. Many clinicians think that laxatives are safe and effective when used judiciously, although the ones with stimulant properties (Dulcolax, Senokot, Ex-Lax, others) may cause some cramping. Laxative herbal teas can also help; patients are advised to start with a weak brew, and gradually increase the strength until it works for them.
Diarrhoea.Bulking agents are generally not useful for diarrhoea. Loperamide (Imodium) reduces intestinal contractions and fluid secretion in the gut. It helps relieve diarrhoea, but not pain. The prescription drug diphenoxylate (Lomotil) may also be useful. Fatty foods, coffee, and alcohol can trigger cramps and diarrhoea. So can chewing gum and drinks containing sorbitol or the sugar fructose. Fructose is found naturally in honey and certain fruits, and it's added as a sweetener to many food products.
Gas and bloating.Simethicone-based products (Gas-X, Maalox, Mylanta, Phazyme, others), charcoal, and alpha-galactosidase (Beano) aren't very effective in relieving gas problems. Prescription drugs aren't much help either. The best approach is to avoid the foods that tend to trigger these symptoms. Some common offenders are beans, pretzels and bagels, milk products, carbonated beverages, bananas, apples and other raw fruits, and vegetables such as cabbage, cauliflower, and broccoli. It is a good idea to try eliminating these foods one at a time, to find out which ones cause trouble. It's also important to rule out lactose intolerance as a cause of symptoms.
Pain.Antispasmodics - including dicyclomine (Bentyl) and hyoscyamine (Anaspaz, Cystospaz, Levsin, others) - help relieve pain by reducing bowel spasms. Low doses of tricyclic antidepressants, such as amitriptyline (Elavil) and nortriptyline (Aventyl, Pamelor), taken at bedtime, may alleviate abdominal pain. (These drugs should be used only for diarrhoea-related IBS, because they can cause constipation). The effects of selective serotonin reuptake inhibitor, or SSRI, antidepressants on IBS symptoms haven't been studied extensively. A heating pad may ease abdominal pain, and caffeine-free herbal tea such as chamomile can be soothing. Some people have found that peppermint oil helps reduce spasms. However, people who have gastroesophageal reflux disease, or GERD, should avoid peppermint oil, because it can make reflux symptoms worse.
This article is provided courtesy of Harvard Medical International. © 2007 President and Fellows of Harvard College.
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