By Kim Chandler

Associated Press

MONTGOMERY — An attorney for a condemned inmate said Alabama's new lethal injection drug combination needs to be scrutinized by the courts before it is used because it relies on a drug involved in two recently botched executions.

Lawyers for death row inmate Tommy Arthur on Friday filed paperwork with the Alabama Supreme Court opposing the state's request to set an execution date for him.

One of Arthur's lawyers said the state is trying to put Arthur to death before courts have assessed the constitutionality of the new three-drug combination adopted by the Department of Corrections.

"Judicial review of this significantly changed protocol is especially critical because the state of Alabama plans to use as the first drug — midazolam hydrochloride — the same drug used in several recently botched executions in other states, including those of Dennis McGuire in Ohio and Joseph Wood in Arizona," attorney Suhana S. Han wrote.

McGuire, an Ohio inmate, took 25 minutes to die during a January execution. Wood took nearly two hours to die in an Arizona execution.

Han said problems suggest the first drug given to inmates, midazolam, is unreliable as an anesthetic. She says an inmate would feel excruciating pain as the final drug, potassium chloride, stops his heart.

"Potassium chloride is an extremely caustic substance that activates sensory nerve fibers inside the veins, causing a prolonged and intense burning sensation," Han wrote.

Han said it would also be premature to set an execution date because of Arthur's ongoing federal challenge to the state's lethal injection process and because a federal court had issued a stay of execution.

The attorney general's office did not have an immediate response to the Arthur court filing. State lawyers said last month that the new procedure is virtually identical to that used by Florida.

Arthur was convicted of the 1982 murder-for-hire of a Muscle Shoals man.

Alabama last executed an inmate in 2013 and has been unable to carry out lethal injections since running out of a drug used under the old protocol.

The Department of Corrections adopted a new lethal injection procedure in September and the attorney general's office moved to seek execution dates for nine inmates who have spent between 16 and 24 years on Alabama's death row.

Gov. Robert Bentley has said he is confident the procedure does not violate the constitutional protection against cruel and unusual punishment.

The new drug protocol calls for the sequential injections of 500 milligrams of midazolam hydrochloride,a sedative; 600 milligrams of rocuronium bromide, a neuromuscular blocking agent that stops breathing; and 240 "milliequivalents" of potassium chloride to stop the heart.

Two states, Florida and Oklahoma, have used midazolam as the first drug in a three-drug protocol, according to the Death Penalty Information Center. Ohio and Arizona have used midazolam in a two-drug protocol.