Tegaserod

Tegaserod is a prescription drug that was originally used for the short-term treatment of women with Irritable Bowel Syndrome (IBS) whose primary bowel symptom was constipation. The Food and Drug Administration (FDA) approved the use of tegaserod in July 2002, and Novartis began to market tegaserod under the name Zelnorm. In March of 2007 the FDA requested that Novartis remove tegaserod from the market because of the increased risk of heart attacks and strokes associated with its use. Health Canada removed tegaserod from the Canadian market at the same time. Now, tegaserod is only available in special situations (see video below).

Other Names

Tegaserod was also sold under the name Zelmac.

Uses

Tegaserod was used in women over the short-term to relieve constipation due to IBS. For this use, the primary symptom of IBS had to have been constipation. Tegaserod was also used to relieve chronic constipation for which the cause was not known.

How Tegaserod is Taken

Tegaserod was available in 2-mg or 6-mg tablets. Typically, a 6-mg dose of tegaserod was prescribed over a four- to six-week period. Women successfully treated after this time were offered a treatment extension for and additional four to six weeks.

How Tegaserod Works

Chronic constipation, whether as part of IBS or due to an undetermined cause, results from the inability of the lower gastrointestinal tract to move waste through the intestine. The neurotransmitter serotonin, which is also called 5-hydroxytryptamine, helps regulate actions of the intestines. Neurotransmitters are chemicals released from nerves that activate other nerves or muscles. Serotonin acts by binding to receptors on these nerves or muscles.

Serotonin is thought to play an important role in chronic constipation and IBS. Tegaserod activates serotonin receptors in the intestine and helps normalize bowel function.

How the Body Affects Tegaserod

Tegaserod reaches a maximum concentration in the blood approximately one hour after dosing. It is altered, or metabolized, in preparation for excretion from the body. It is metabolized in both the stomach and liver. Most (about two-thirds) of tegaserod is excreted in the feces.

Side Effects

The following are side effects experienced during tegaserod use during three clinical trials:

• Heart problems such as rapid heartbeat, chest pain and low blood pressure leading to fainting
• Vertigo
• problems with vision
• gastrointestinal effects such as Hemorrhoids, pain in the rectum, stomach discomfort, fecal incontinence, IBS, indigestion, gastroesophageal reflux disease, and stomach inflammation
• Chest pain
• edema (fluid accumulation)
• gallstones
• allergic reactions
• increased appetite
• Psychiatric disorders (e.g., Depression, sleep disorder, restlessness)
• breathing difficulty
• miscarriage and heavy menstruation
• Vascular disorders (e.g., Flushing, low blood pressure)

The most common side effects, such as diarrhea, involve the gastrointestinal tract.

Risks and Precautions

Serious consequences of diarrhea in clinical trials of tegaserod have been reported. These include low blood volume, low blood pressure, and fainting.

After tegaserod entered the market, reports of ischemic colitis surfaced. Ischemic colitis is a condition in which inflammation develops in the colon.

Tegaserod is not used in people with the following conditions:

• severe kidney impairment
• moderate or severe liver damage
• a history of blockages in the bowel
• uncontrolled gallbladder disease
• allergy or hypersensitivity to tegaserod or any of the components of Zelnorm

Drug Interactions

To date, there is no evidence of clinically significant drug interactions with tegaserod.

Controversy

Data from Novartis were examined by two independent reviewers to determine if tegaserod use was associated with an increased risk of cardiac events, such as angina.^[1] The data showed that 0.11% of people treated with tegaserod experienced some cardiac event and this risk was ten times higher than that for the general population. This increased risk caused Novartis to remove tegaserod from the market. However, Novartis suggests that the drug may still be of some use in specific patient populations, and its potential re-instatement as a treatment for constipation is being investigated.^[1]

Research

In three clinical trials, over 2,000 women with at least a three-month history of IBS that included abdominal pain, bloating and constipation received either 6 mg of tegaserod or placebo twice daily.

During the first month, 8%–11% more tegaserod-treated patients than placebo-treated patients responded to treatment with respect to abdominal pain/discomfort. Similarly, 9%–12% more tegaserod -treated patients than placebo-treated patients had significant relief of bloating.^[2]

References

1. ↑ ^{1.0 1.1} Zelnorm. Novartis suspended US marketing and sales of Zelnorm upon request from FDA. PDF.
2. ↑ Pharma-Help. Zelnorm Clinical Trials and Studies

External Links

Zelnorm Home Page

HelpforIBS.com: Zelnorm

FDA: Zelnorm (tegaserod maleate) Information

RxList: Zelnorm