RAPID CITY, S.D. (AP) – A South Dakota death row inmate, who’s scheduled to be executed next month, has taken issue with the state’s choice of the drug that will take his life.

Charles Russell Rhines was convicted of killing 22-year-old Donnivan Schaeffer, while burglarizing a Rapid City doughnut shop, in 1992.

Rhines is asking the state to follow the law on lethal injections at the time he was sentenced to death in 1993. That’s when a protocol of an ultra-short-acting lethal drug, and a chemical paralytic, was used.

For Rhines’ execution, the state intends to use pentobarbital, commonly used to euthanize animals.

Rhines is asking a judge to stop the execution until his request is decided.