SIOUX FALLS, S.D. (AP) – Attorneys for a South Dakota prisoner facing execution next week are arguing he should be able to choose the drug to be used in his lethal injection.

Charles Russell Rhines is to be executed with pentobarbital, which several states have used to administer the death penalty. But Craig Stevens, a professor of pharmacology at the University of Oklahoma, testified on Rhines’ behalf Tuesday that it’s not an “ultra-short-acting” drug.

The state cited testimony from one of its expert witnesses, an anesthesiologist who said there’s no difference in the way pentobarbital and drugs classified as “ultra-short-acting” work in an execution.

Judge Jon Sogn said he would rule as quickly as he could. But he gave the state until Wednesday to seek more time or submit additional testimony.