General Information

Zelnorm aids in the movement of stools through the bowels by selectively activating 5HT4 receptors present throughout the gastrointestinal tract. Zelnorm has been approved by the FDA for the short-term treatment of women who have irritable bowel syndrome (IBS) with constipation as their main symptom. Other problems associated with IBS include abdominal pain and bloating. Although Zelnorm treats the symptoms of IBS, it is not a cure for the disorder.

In March of 2007 Zelnorm was removed from the market following evidence of a link between the drug and an increased risk of heart attack, stroke and angina.

Clinical Results

Three multicenter, double blind, placebo-controlled studies evaluated Zelnorm in 2,470 women with irritable bowel syndrome (IBS) symptoms, namely abdominal pain, bloating and constipation. Two studies were fixed dose studies and the third was a dose-titration study. In all three studies Zelnorm was administered for 12 weeks and efficacy was evaluated based on patients' ratings of their relief of symptoms and the intensity of symptoms. Zelnorm-treated patients reported greater relief from symptoms and greater increase in number of stools than placebo-treated patients, with the difference being largest during the first four weeks.

Mechanism of Action

Tegaserod is a partial agonist that binds with high affinity at human 5-HT4 receptors, whereas it has no appreciable affinity for 5-HT3 or dopamine receptors. It has moderate affinity for 5-HT1 receptors. Tegaserod, by acting as an agonist at neuronal 5-HT4 receptors, triggers the release of further neurotransmitters such as calcitonin gene-related peptide from sensory neurons. The activation of 5-HT4 receptors in the gastrointestinal tract stimulates the peristaltic reflex and intestinal secretion, as well as inhibits visceral sensitivity (From FDA Label).