Swiss pharmaceutical giant Novartis yesterday announced having suspended the sales of its drug Zelnorm, used in the treatment for constipation caused by irritable bowel syndrome after the US Food and Drug Administration said the product carried the risk of heart problems or strokes.

The drug had been approved in July 2002, for women who had the complication, and in August, 2004, the drug was considered safe for use by men and women under 65.

However, under an ongoing review, Novartis analysed data from more than 18,000 patients and its researchers found that 13 out of 11,614 patients treated with the drug experienced events like heart attack, stroke, or angina. Only one in 7,031 placebo-treated patients experienced such events. All patients affected had pre-existing cardiovascular disease.

"My review of the data suggested that a causal relationship is unlikely" between heart problems and Zelnorm use, said Jeffrey L. Anderson, MD, an independent cardiologist at the University of Utah who reviewed the data. "Furthermore, the data did not show any consistent pattern of event type, time to event or dose relationship in tegaserod-treated patients."

But the FDA is now advising patients who are using Zelnorm to contact their health care providers to discuss treatment alternatives. "Patients who are taking Zelnorm should seek emergency medical care if they experience severe chest pain, shortness of breath, dizziness, sudden onset of weakness or difficulty walking or talking, or other symptoms of a heart attack or stroke," the FDA said in a press release yesterday.

The FDA is still working with Novartis to allow access to Zelnorm as an investigational drug for patients with no other treatment options, or in other cases where the benefits may outweigh the risks.