Irritable Bowel Syndrome Medication: Update on Zelnorm

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. Starting in 2007, the drug Zelnorm was available in the United States through a “treatment IND” (investigational new drug). However, research showed that people taking the drug had serious side effects including heart attacks, strokes, and unstable angina (severe chest pain that could be a warning for a future heart attack). In 2008, Novartis voluntarily stopped the Zelnormtreatment IND. Today, FDA allows limited access to the drug on an individual basis and in emergency situations. Emergency use is defined as situations that are “life-threatening” or that require the patient to go to hospital for care. Access to Zelnorm will be denied in any of the following conditions: prior history of heart attack or stroke, unstable angina, hypertension (high blood pressure), hyperlipidemia (elevated blood cholesterol and other fats), diabetes, age greater than 55 years, smoking, obesity, depression, anxiety, suicidal ideation.[2].

How Did Zelnorm Get on the Market?

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.

What Are Options for Managing IBS?

There are many much safer ways to treat constipation, including adding fiber to your diet (such as whole grain bread or other high fiber bread, nuts, and fresh fruits and vegetables), exercise, 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, packaged fruit or vegetables, 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 allows providers access to the drug through their expanded access program (see the Zelnorm single patient IND packet here).  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 than Zelnorm.

Off-Label Uses of Zelnorm

Since Zelnorm works by stimulating the movement of the gastrointestinal tract, it has been tested in a condition of slowed stomach emptying, known as gastroparesis. Gastroparesis can be caused by diabetes but in many cases, the cause is unknown (this is called idiopathic gastroparesis). If a patient has diabetes, he/she is likely to have increased risk for heart attack and strokes, and those patients are not allowed access to Zelnorm because of the risks.  One small study reported on 3 patients in the intensive/critical care wards who benefited from Zelnorm.[4] In this instance, Zelnorm was used in an emergency/critical situation. More studies are needed to determine whether harms outweigh benefits in non-emergency settings.[5]. Currently, there are no registered clinical trials investigating Zelnorm (you can search all registered clinical trials here).

Metoclopramide is the only FDA-approved treatment for gastroparesis, however it carries a black-box warning for irreversible neurological damage. You can read more about gastroparesis and treatment options here [6]. Talk with your doctor about safe options that may work for you.

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.


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

2.    U.S. FDA. Postmarket Drug Safety Information for Patients and Providers: Zelnorm (Tegaserod maleate). (March 2016). Available online:

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

4.    Banh HL, MacLean C, Topp T, Hall R. The use of tegaserod in critically ill patients with impaired gastric motility. Clin Pharmacol Ther. 2005 Jun;77(6):583-6.

5.    Liu N, Abell T. Gastroparesis Updates on Pathogenesis and Management. Gut and Liver. 2017;11(5):579-589. doi:10.5009/gnl16336.

6.    National Institute of Diabetes and Digestive and Kidney Diseases. Gastroparesis. (June 2012). Available Online: