LOUISVILLE, Ky. (AP) — A Kentucky death-row prisoner claims that giving a condemned inmate a sedative on the day of execution interferes with the drug cocktail used in lethal injections.

The lawsuit by Gregory L. Wilson, 51, is a new challenge to Kentucky's execution method after the U.S. Supreme Court agreed to hear arguments from two other death-row inmates who claim it amounts to cruel and unusual punishment.

The high court has allowed just one execution since agreeing to hear arguments in January in a case that could affect how executions are carried out in 36 states.

Wilson's new lawsuit challenges the method rather the constitutionality of Kentucky's execution procedure. Sedatives interfere with the effectiveness of sodium thiopental, a fast-acting barbiturate used during execution that renders an inmate unconscious, Wilson's attorneys claim in the challenge filed Wednesday in U.S. District Court in Frankfort.