Background : Tegaserod is a 5-hydroxytryptamine-4 receptor partial agonist. Oral administration causes gastrointestinal effects resulting in increased gastrointestinal motility and attenuation of visceral sensation.

Aim : To determine the long-term safety and tolerability of tegaserod in patients suffering from irritable bowel syndrome with constipation as the predominant symptom of altered bowel habits.

Method : A multicentre, open-label study with flexible dose titration of tegaserod in out-patients suffering from constipation-predominant irritable bowel syndrome.

Results : A total of 579 patients with constipation-predominant irritable bowel syndrome were treated with tegaserod. Of these, 304 (53%) completed the trial. The most common adverse events, classified as related to tegaserod for any dose, were mild and transient diarrhoea (10.1%), headache (8.3%), abdominal pain (7.4%) and flatulence (5.5%). Forty serious adverse events were reported in 25 patients (4.4% of patients) leading to discontinuation in six patients. There was one serious adverse event, acute abdominal pain, classified as possibly related to tegaserod. There were no consistent differences in adverse events between patients previously exposed to tegaserod and those treated de novo. No pattern-forming tegaserod-related abnormalities in haematological and biochemical laboratory tests, urinalysis, blood pressure, pulse rate or electrocardiograms were found.

Conclusions : Tegaserod appears to be well tolerated in the treatment of patients with constipation-predominant irritable bowel syndrome. The adverse event profile, clinical laboratory evaluations, vital signs and electrocardiogram recordings revealed no evidence of any unexpected adverse events, and suggest that treatment is safe over a 12-month period.