Having restricted its use last year, Novartis has now served notice that it intends to take its irritable bowel syndrome off the US market completely.

The Swiss drugs giant has notified the US Food and Drug Administration that it will no longer provide Zelnorm (tegaserod maleate) as part of a restricted programme agreed with the agency in July last year. That agreement saw Novartis provide the drug to treat IBS with constipation and chronic idiopathic constipation in women younger than 55 who meet certain conditions.

However, the product was being treated as an investigational new drug and patients needed to meet strict criteria and have no known or pre-existing heart problems. Zelnorm, known elsewhere as Zelmac, had been off the US market for general use since March 2007 when Novartis suspended sales because a safety analysis found a higher chance of heart attack, stroke, and unstable angina in patients treated with Zelnorm compared with placebo.

Now the FDA reports that Novartis will only supply Zelnorm for use in emergency situations only and requests for the drug must be made to the agency which in turn would authorise shipment from the manufacturer. An emergency situation is defined as one that is “immediately life-threatening or serious enough to qualify for hospitalisation”.

However the FDA may still deny authorisation “if exposure to Zelnorm would pose an unreasonable or a significant additional risk to patients”. Conditions to stop the drug being prescribed include a history of heart problems, diabetes, smoking, obesity, and depression, and Zelnorm could also be denied to people aged over 55.

The loss of Zelnorm last year was a major blow for Novartis as the drug brought in $561 million in 2006, though first-half 2007 sales fell 66% to $91 million as the effect of the suspension kicked in. The company has not revealed why it has completely pulled the plug on the treatment.