Danish pharmaceutical company Lundbeck has moved to stop a drug it produces from being used to execute prisoners in the United States.

Chief executive Ulf Wiinberg said the company will demand that distributors in the United States sign an agreement stating they will not make pentobarbital - a sedative with a range of medical uses - available for prisons using it for lethal injections.



"Lundbeck will have to approve each order and everyone buying the product must sign a paper stating they will not sell it on to prisons," Mr Wiinberg said today.



Death penalty opponents had urged the company to take stronger action, such as rewriting distribution contracts with clauses prohibiting sales of pentobarbital to US prisons. The company initially had rejected that idea, saying it would be impossible for distributors to follow up on how every vial is used.



"It is an expensive method, it is a laborious method, and no one has done that before. But that is what we are doing now," Mr Wiinberg said.



Lundbeck - the only company that makes the drug - found itself in an awkward situation in January as death penalty states in America started switching to pentobarbital for lethal injections to replace another chemical that's no longer readily available.

The Copenhagen-based company has complained about its product being misused and has written letters to prison authorities and governors in American states asking them not to use it.



Mr Wiinberg said the company also has discussed the issue with shareholders and human rights organisations.



"I have not experienced any pressure from our shareholders," he said. "My understanding is that they have felt that we did the right thing."



The uses of pentobarbital, which is produced by Lundbeck's plant in Kansas, include treatment of epileptic seizures, but it has become a key element in US executions.

AP