SIOUX FALLS, S.D. (AP) — A South Dakota judge has denied a state inmate’s request to delay his execution over the drug to be used.

Charles Rhines argues that pentobarbital does not act quickly enough to comply with state law.

But Circuit Judge Jon Sogn rejected that argument Thursday, writing in a 23-page order that when the drug is used in lethal doses it operates “virtually the same” as other drugs that Rhines had cited. And Sogn wrote that it may even work more quickly.

Rhines’ execution is scheduled for next week, but officials have not released the exact date.

Pentobarbital has been used in recent executions in Georgia, Missouri and Texas, as well as in South Dakota.

The 63-year-old Rhines killed a 22-year-old doughnut shop employee, Donnivan Schaeffer, who interrupted him during a burglary in Rapid City.