New execution drug approved.

A drug used to euthanize animals has been approved for use in capital punishment in Oklahoma, a decision that could affect other states scrambling to address a nationwide shortage of a key anesthetic used in executions.

The shortage of thiopental sodium, an anesthetic long used by states to carry out lethal injections, had prompted Oklahoma to seek court clearance to use pentobarbital as a substitute.

In Oklahoma City Friday, U.S District Judge Stephen Friot approved the use of pentobarbital and denied requests to delay the executions of two Oklahoma inmates, whose attorneys had protested its use.

The state has said in court filings that veterinarians regard pentobarbital "as an ideal anesthetic agent for humane euthanasia in animals" and that it is "substantially" similar to thiopental.

Oklahoma's lethal-injection procedure, like that of most other death-penalty states, involves injecting thiopental to render an inmate unconscious before other drugs are injected to cause paralysis and stop an inmate's heart.

Judge Friot's ruling could prompt other states to use pentobarbital, and thus prevent delays in capital punishment triggered by the thiopental shortage. In the early 1970s, Oklahoma was the first state to approve the use of thiopental in capital punishment, and it later become the nationwide standard for lethal injections.

Hospira Inc., the sole U.S. maker of thiopental, has announced that it won't resume production of the drug until 2011, at the earliest, citing a shortage in one of thiopental's raw ingredients. Hospira also has stated it doesn't support the drug's use in executions.

The injectable form of pentobarbital is made by Wyeth Ayerst, according to the Food And Drug Administration; Wyeth is a unit of Pfizer Inc.

Pfizer did not respond to a request for comment.

The lack of thiopental has played a role in delayed executions in California and other states. Many states, including Arizona, Kentucky and Tennessee, have combed domestic or overseas suppliers in search of thiopental. Other states such as Texas have a sufficient stockpile on hand to cover near-term executions, but they could run into delays next year if Hospira doesn't make a new supply.

Attorneys for inmates facing execution in Oklahoma have contended that the state should not be able to use an unproven drug. They say its use would violate the inmates' constitutional protections against cruel and unusual punishment. Pentobarbital has never been used for capital punishment, attorneys said.

Oklahoma stated in court filings that pentobarbital has been used to induce comas in humans and further that the drug, like thiopental, is a central nervous system depressant that can effectively render a person unconscious.

An attorney for Oklahoma inmate John David Duty, who is due to be the next person executed in the state, on Dec. 16, did not return requests for comment. Attorneys for Oklahoma inmate Jeffrey Matthews, whose execution has not yet been scheduled, also did not return requests for comment.

Spokesmen for the Oklahoma Department of Corrections and attorney general's office did not return requests for comment.

"Given the troubling history and present of lethal injection . . . it is extraordinary that such an important decision [to switch anesthetics] is made in so little time with basically only snippets of medical input," said Deborah Denno, a professor at Fordham University School of Law who specializes in the law governing lethal injections.

"We have to ask ourselves in this country ─ what is the rush?," she said.