LUCASVILLE, Ohio (AP) -A condemned Ohio killer is set to be executed using a never-tried lethal injection method.

The U.S. Supreme Court refused Dennis McGuire a stay of execution. He would be the first prisoner put to death in the U.S. by the two-drug combination if his execution proceeds Thursday.

Ohio adopted the use of the sedative and painkiller after supplies of its previous execution drug dried up when its manufacturer put it off limits for capital punishment.

McGuire's attorneys argue he'll experience agony and terror as he struggles to breathe. The state disputes that scenario.

The 53-year-old McGuire was sentenced for the 1989 rape and fatal stabbing of Joy Stewart in western Ohio's Preble County.

A prisons spokeswoman says McGuire was calm and cooperative when he arrived at the death house Wednesday.