Zelnorm, known generically as tegaserod, is a novel type of medication for the treatment of constipation-predominant irritable bowel syndrome (IBS). For many patients, tegaserod was the only medication that was effective in treating this condition over the long term. Unfortunately, it was recently withdrawn from the market because of heart complications in a small number of patients. Tegaserod worked through the serotonin pathway, and unfortunately, no similar medications are available. However, there remain certain strategies that work in constipation-predominant IBS, including dietary changes, fiber supplements, anxiety reduction, and so forth, so talk to your doctor about all of your options rather than waiting for a newer, more effective drug. Q2. I think I have irritable bowel syndrome (IBS) with constipation. I have been taking magnesium sulfate to see if that will help. I was wondering how much at a time is safe. What I have been taking is not working; can I keep upping the dose until it does? Magnesium salts, including magnesium sulfate, magnesium citrate, and magnesium hydroxide, have long been popular in the treatment of constipation. They work mostly by an osmotic mechanism, meaning that the magnesium salt draws water out of the gut wall into the intestine, thereby softening the stool. By and large, these magnesium salts are very safe because the kidney can normally excrete any excess magnesium. The intestine also responds to high magnesium levels in the blood by absorbing less magnesium from the gut as a secondary backup mechanism. However, elderly patients or patients with kidney disease can’t handle ingested magnesium as well, resulting in hypermagnesemia (too much magnesium in the blood). Side effects of high magnesium levels include nausea, vomiting, lethargy, low blood pressure, low pulse rate, difficulty breathing, and in extreme cases, coma and death. Even in younger patients with normal kidneys, magnesium sulfate should not be used at a dose of more than 10 gm per day or for more than one week without a doctor’s supervision. Q3. Is there a new medicine that replaces Zelnorm yet? I have IBS with constipation and GERD and was taking Zelnorm, Amitiza, Nexium, and Lactulose (all two times daily), and that worked great for me. But after Zelnorm was found to cause heart attacks, I have been off it and have had major constipation. No, there is no specific replacement for Zelnorm at this time. Reglan may help you, as may an osmotic laxative like milk of magnesia, or Miralax. Citrate of magnesium is another good choice. Editor’s note: In March 2007, the FDA issued a public health advisory stating that Novartis Pharmaceuticals Corporation had agreed to take Zelnorm (tegaserod maleate) off the market because a safety analysis found that patients taking the drug had a higher risk of having a heart attack, stroke, or worsening chest pain that could lead to a heart attack compared with patients treated with a placebo pill they thought was Zelnorm. Until that time, Zelnorm had been approved for short-term treatment of women with irritable bowel syndrome with constipation and for patients younger than age 65 with chronic constipation. The total number of patients on Zelnorm who actually had heart attacks or severe chest pain that turned into a heart attack was small, but these side effects were considered serious and potentially life-threatening. Q4. I have IBS with constipation and have been taking Metamucil daily for the past couple of years. It helps a lot. But I’ve noticed I can’t have a bowel movement now without it. Can taking this for a long period of time do more harm than good? – Kelly, Canada The answer is no. Metamucil is one of several commercial products on the market containing psyllium. This fiber serves to soften stool over the long-term by bulking it up, attracting water to make the stool softer, and changing the bacterial flora of the stool to those that promote healthy bowel habits. Metamucil and other fiber products are not absorbed and do not worsen constipation over time, in contrast to many over-the-counter laxatives that deplete neurotransmitters (natural chemicals that stimulate our muscles) in the colon and are associated with worsening constipation after months or years of use. Metamucil has no known harmful effects even after taking it for years. In fact, fiber products, when used regularly over a long period of time, may reduce blood cholesterol levels and offer some protection against colon cancer. Learn more in the Everyday Health Irritable Bowel Syndrome Center.
