Ortho McNeil has launched an extended-release version of the opioid analgesic tramadol, which has been tipped as a potential blockbuster product, in the USA.

Ultram ER is a once-daily formulation of the widely-used painkiller, which has to be given up to six times a day for the immediate-release version. The extended-release formulation was developed by Canadian generics company Biovail and licensed last November to Ortho, a subsidiary of Johnson & Johnson, which originally launched tramadol in 1995.

Ortho sells immediate-release tramadol under the Ultram brand name and as Ultracet (tramadol plus acetaminophen), and said in its fourth-quarter 2005 results statement that the latter product had been hit hard by generic competition, contributing to a 3% shrinkage in US pharmaceutical sales at J&J. Prior to the onset of copycat rivals to Ultracet the product had been bringing in sales of around $385 million a year.

Analysts have said Ultram ER could be a billion dollar product in its own right. It was approved by the US Food and Drug Administration (FDA) in 100mg, 200mg and 300mg strengths in September, and is the only once-daily formulation of the drug registered there.

In Europe, a once-daily version of tramadol developed by Canadian firm Labopharm is already on the market, debuting in France last January. This version has been licensed to Purdue Pharma in the USA and is in Phase III testing there.

Meanwhile, Biovail has also licensed a quick-dissolve formulation of tramadol to Ortho. This version, called Ultram ODT, was approved by the FDA last May and is also expected to help defend Ortho’s tramadol franchise from generic rivals.