Irritable Bowel Syndrome Medication: Zelnorm and Treatment INDs

Keris KrennHrubec and Diana Zuckerman, PhD

February 2008

Irritable bowel syndrome (IBS) is an uncomfortable intestinal problem that affects nearly one in five Americans,1 most of whom are women. IBS symptoms may include severe abdominal pain, cramping, constipation, and diarrhea, but the illness is hard to diagnose because of how vague and varied the symptoms can be. A person’s diet and stress level can contribute to IBS,1 although it has not been linked to any bacteria, virus, or gene. Unfortunately, known treatments only help with IBS symptoms, not the cause. Most patients will not experience symptoms bad enough to seek medical treatment, but there are many drugs available for treating those who do. However, recent studies have shown that some of these treatments can cause dangerous side effects, such as heart attacks, strokes, and severe diarrhea.2 So how is it that these drugs are still on the market if they are unsafe? The answer is because of a drug development process known as “treatment IND” (Investigational New Drug).

Treatment INDs

In 1987, the Food and Drug Administration (FDA) developed a program that would allow dangerously ill patients to access new drugs that were still in clinical trials.3 If a drug was being tested and initially seemed to be effective and safe, then under the “treatment IND” plan, the drug could be prematurely released to very sick patients.3 The process was designed for drugs that would treat life-threatening diseases where patients could die waiting for the clinical trials to be completed, but could potentially be helped if they got the medication sooner.3

In the 11 years between the 1987 program’s beginning and 1998, only 39 applications for this kind of drug trial were approved by the FDA.3 Of these, 13 were for cancer treatments, and 11 were for HIV/AIDS.3 Today, however, treatment INDs are being used to get medications to many different kinds of patients without going through the normal process of full clinical trials, and some of these are drugs that have been shown to have dangerous side effects. The most recent of these is an IBS medication called Zelnorm, made by Novartis.


Despite the lack of data on men and concerns about side effects such as diarrhea,4 Zelnorm was approved by the FDA for women’s use in 2002. Approval was based on its effectiveness in treating constipation among women with IBS, although constipation is only one of the symptoms of IBS. In March 2007, Zelnorm was abruptly taken off the market because of reports of high rates of heart attacks, strokes, and angina (intense chest pain associated with coronary artery disease).2 In some cases, it also resulted in severe diarrhea, as well as a condition where blood flow is significantly limited and can cause part of the colon to die.2

Amazingly, just three months later, Zelnorm returned to the market under the treatment IND title. It can now be prescribed only for women under age 55 who are not already at risk for heart disease.2 So why is anyone allowed to take a medication for constipation that increases the risk for potentially fatal heart disease? An even bigger question is why is Zelnorm, a drug that treats constipation, is sold and marketed for IBS, a more complicated and serious illness?

Should I Take Zelnorm For My IBS?

Zelnorm has been shown to put women who were already at risk for heart disease at greater risk. Zelnorm may help relieve constipation that is often associated with IBS; however, there are many other ways to treat constipation, including adding fiber to your diet (such as high fiber bread, fruits, and vegetables), exercise to decrease stress, and over-the-counter remedies such as Metamucil. Fiber is listed on all food packages, so check the fiber content listed on packaged bread, crackers, muffins, cranberry sauce, dried or canned fruit, or look at a fiber chart for fresh fruits and vegetables. Here’s a chart that can help you: You’re bound to find something you like.

If these safer alternatives are ineffective, what evidence is there that the benefits of Zelnorm outweigh the risks? The FDA recommends this drug only for those people who have tried all other treatment options and are without alternatives, and states clearly that for most people, the risks of this drug outweigh the benefits.5 Although you can certainly ask your doctor, it makes sense to make a serious effort to try safer alternatives before even considering this medication. Medications under these restricted access programs generally require a signature proving that you understand all of the risks involved before you take it, so if you’re considering it read any forms you are asked to sign very carefully, and ask lots of questions.

If you have IBS rather than constipation, there are several other drugs on the market that do not have the same safety concerns, and are probably more effective.


1 Mayo Clinic. (July 2007). Irritable Bowel Syndrome. Retrieved from:

2 Fugh-Berman, Adriane, MD. (September/October 2007). Unsafe IBS Drugs Back on the Market. The Women’s Health Activist. National Women’s Health Network.

3 US Food and Drug Administration. (February 2006). Treatment IND. Retrieved from:

4 FDA Press Release, July 24, 2002, retrieved from:

5 FDA News. (2007, March 30). FDA Announces Discontinued Marketing of GI Drug, Zelnorm, for Safety Reasons. Retrieved From: