Vidyya Medical News Service
Volume 6 Issue 120 Published - 14:00 UTC 08:00 EST 29-Apr-2004 Next Update - 14:00 UTC 08:00 EST 30-Apr-2004
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Information for patients: Questions and answers on Zelnorm (tegaserod maleate)

1. What prompted FDA to work with Novartis to alert the public to new safety information about Zelnorm?

Since the time of Zelnormís initial marketing in the U.S. in August 2002 through March 2004, FDAís postmarketing adverse event reporting system has received reports of patients taking Zelnorm who experienced serious adverse events.  These reports include 21 patients taking Zelnorm who have experienced serious consequences of diarrhea, 20 patients who have been diagnosed with ischemic colitis, and 3 patients diagnosed with other types of intestinal ischemia.  In some patients, these adverse events have led to hospitalization, surgery, and even death.

As a result, FDA is announcing that the labeling of Zelnorm will be updated to include this important new risk information for doctors and patients.  Although it has not been established that use of Zelnorm caused these adverse events, this new information will allow physicians and patients to better understand the potential risks and benefits of Zelnorm and make informed treatment decisions.

2. What is Zelnorm?

Zelnorm is a medicine used for the short-term treatment of women who have irritable bowel syndrome (IBS) with constipation (hard stools or difficulty passing stools) as their main bowel problem.  IBS is a disorder that interferes with the normal functions of the large intestine (colon).  Symptoms may include cramps, abdominal pain, bloating, constipation, and/or diarrhea.  The cause of IBS is not known.

Zelnorm works by increasing the movement of stools through the bowels.  For those patients who are helped, Zelnorm reduces pain and discomfort in the abdominal area, bloating, and constipation.

Zelnorm is not a cure for IBS and does not work for all women who use it.  FDA does not have evidence that Zelnorm is effective in men with IBS.

3.      3. What new changes are being made to the Zelnorm label?

The major changes to the Zelnorm label include a new warning about serious consequences of diarrhea, a new precaution about ischemic colitis and other forms of intestinal ischemia, and updated labeling for patients that includes information about these potential side effects and advises that patients should stop taking Zelnorm and contact their doctor.

4.      4. What are serious consequences of diarrhea?

Serious consequences that can occur when patients experience large amounts of diarrhea include dehydration, low blood pressure, and fainting.  In some of the reported cases in patients taking Zelnorm, these complications have required hospitalization for rehydration.

5. What is ischemic colitis?

Ischemic colitis is a condition resulting from reduced blood flow to the intestines, which in some cases can cause serious intestinal damage, and rarely death.  Some of the signs and symptoms of ischemic colitis are new or worsening abdominal pain, fever, vomiting, bloody diarrhea, rectal bleeding, and low back pain.

Sometimes ischemic colitis is mild and may resolve by itself.  However, other times ischemic colitis can lead to serious problems requiring surgery and in rare cases can lead to death.

FDA has received 20 reports of ischemic colitis in people taking Zelnorm, however, at this time we are not able to determine whether these events were caused by Zelnorm.  It is possible that these events were not caused by Zelnorm, but rather by some other cause including other diseases that the patient may have or other drugs the patient was taking.

6. What is intestinal ischemia?

Intestinal ischemia is a condition resulting from reduced blood flow to the intestines that can lead to ischemic colitis or to more severe forms of intestinal damage that may require surgery or result in death.

7. Who should not use Zelnorm?

Patients should not start taking Zelnorm if they have:

  • diarrhea now or have diarrhea often
  • bad kidney or liver disease
  • ever had bowel obstruction (intestinal blockage), symptomatic gallbladder disease, or abdominal adhesions causing pain and/or intestinal blockage.

8. How should Zelnorm be taken? 

The recommended dosage of Zelnorm is 6 mg taken twice daily orally before meals for 4 to 6 weeks. For those patients who respond to therapy at 4-6 weeks, an additional 4-6 week course can be considered.

9. Is Zelnorm safe to use?

Patients should understand that all drugs have risks and a determination by FDA that a drug is safe and effective does not mean that the drug is risk free.  FDA will approve a drug if it determines that the benefits of the drug exceed the risks for the approved use as directed by the labeling.  When FDA approves a drug, the labeling includes information on the benefits and risks and the appropriate dosing regimens so that doctors and patients can make informed individual treatment decisions.

Data from clinical trials and post-marketing reports have identified serious consequences of diarrhea in patients treated with Zelnorm and this potential adverse effect appears to be related to the effects of the drug.  In addition, post-marketing reports have identified ischemic colitis and intestinal ischemia as potential adverse effects that may occur in patients receiving Zelnorm.  While the available data do not allow FDA to determine whether the reports of ischemic colitis and intestinal ischemia are caused by Zelnorm, it is important that doctors and patients be aware of these potential risks as they assess the potential benefits of treatment with Zelnorm in individual patients.

Patients should ask their doctor whether Zelnorm is right for them.  Patients should consult their doctor if they develop symptoms such as severe diarrhea, dizziness, fainting, new or worsening abdominal pain, or blood in the stools with or without abdominal pain.

10. Does Zelnorm cause serious consequences of diarrhea?

In some patients Zelnorm can cause severe diarrhea that can result in dehydration, low blood pressure, dizziness, fainting, or the need for hospitalization.

11. Does Zelnorm cause ischemic colitis and intestinal ischemia?

At this time we donít know if Zelnorm is causing ischemic colitis or intestinal ischemia.  We donít know if these events are due to another reason such as an interaction with another medical condition or an added medication.  However, because of the reports of ischemic colitis and intestinal ischemia in Zelnorm users, FDA would like the medical community and patients to be aware of the possible link.  This will allow patients to seek prompt medical care should they get any of the signs or symptoms of ischemic colitis.

12. What are other side effects of Zelnorm?

The most common side effects of Zelnorm include:

  • Headache

  • Abdominal pain

  • Diarrhea

  • Nausea

  • Dizziness

These are not all the possible side effects of Zelnorm.  Doctors or pharmacists can provide patients with additional information on the side effects of Zelnorm.

13. Are there other drugs used to treat IBS with constipation?

Patients are often treated with diet, exercise, fiber, and various medicines to help relieve constipation.  There is no other FDA approved medication for IBS with constipation.

14. If a patient wants to discuss their treatment with Zelnorm what should they do?

Patients should discuss questions and concerns with their doctor.

If patients have further questions about Zelnorm, they may contact the Center for Drug's Division of Drug Information at: 888-INFO.FDA (888-463-6332), or email us at:

Patients may also contact Novartis directly at 1-862-778-8300.

15. Is Zelnorm going to be taken off the market?

FDA is not thinking of taking Zelnorm off the market at this time.  We are adding new information about potential risks of treatment with Zelnorm to the labeling so that doctors and patients can make informed individual treatment decisions.  FDA is also encouraging doctors and patients to report any similar events to FDA so that we can further understand these events and their association with Zelnorm use.

Todayís announcement by FDA and Novartis is an effort to minimize risks and maximize benefits of Zelnorm by ensuring that patients and doctors fully understand these risks and benefits.

16. Is Zelnorm going to have restricted marketing like Lotronex?

FDA has not requested any restrictions on the marketing or distribution of Zelnorm.  We will continue to carefully evaluate post-marketing reports in patients receiving Zelnorm and consider any additional changes to labeling or other risk management steps that may be necessary as we gain a better understanding of these events.  We encourage doctors and patients to report possible adverse events to FDAís MedWatch program at or call 1-800-FDA-1088.

17. What should patients do if they think they are having side effects from Zelnorm?

Patients should call their doctor right away if they think they are having side effects from Zelnorm. 

FDA has received reports of Zelnorm users who have fainted because of low blood pressure due to severe diarrhea caused by Zelnorm.  FDA is advising patients who faint while taking Zelnorm to stop the drug immediately and see their doctor at once.

If patients experience blood from the rectum, bloody diarrhea, and/or new or worse abdominal pain, they should stop taking Zelnorm immediately and see their doctor who may need to perform additional tests.

To gather more safety information about Zelnorm, FDA is asking that doctors and patients report cases of suspected adverse effects from Zelnorm to FDAís MedWatch Program at: and click on "How to Report" or by calling 1-800-FDA-1088.

18. Does the current labeling for Zelnorm warn about diarrhea?

Yes, the first FDA approved labeling for Zelnorm described cases of diarrhea that were seen in clinical trials.  Postmarketing surveillance has identified additional cases of diarrhea, some of which were serious enough to cause low blood pressure and fainting and the need for hospitalization for intravenous fluids.  FDA has been working with the company to update its labeling to emphasize the serious nature of the diarrhea that some users might experience.

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Date created: April 28, 2004

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