A death row inmate in Georgia wants to be executed by a firing squad, claiming that lethal injection would be too painful for him, CNN reported.

Convicted murderer J.W. Ledford Jr. is scheduled to be executed by lethal injection on Tuesday. He currently takes a pain medication called gabapentin. In documents filed by his lawyer in U.S. District Court, Ledford claims the drug has changed his brain chemistry so much, the lethal injection drug pentobarbital might not render him unconscious, causing him "to suffer an excruciating death."

"Mr. Ledford proposes that the firing squad is a readily implemented and more reliable alternative method of execution that would eliminate the risks posed to him by lethal injection," his lawyers said.

The Georgia attorney general's office responded Friday, saying there was no proof a firing squad would be less painful and contended there was "no substantial risk" he would suffer severe pain in a Georgia execution by lethal injection.

"Plaintiff has waited until the eve of his execution to suddenly claim that he has been treated for pain with medication that will allegedly interfere with his execution," the state's lawyers wrote. "If plaintiff really thought the firing squad was a reasonable alternative he could have alerted the State years, instead of 5 days, before his execution."

Legal precedent only allows him to suggest an alternative form of execution allowed by Georgia, but the state only authorizes lethal injection, the lawyers wrote. Ledford's "dilemma illustrates why this standard is unworkable," the lawyers said.

Ledford has been on death row for 25 years. He was convicted of murder and other crimes in the death of an elderly neighbor, Dr. Harry Buchanan Johnston Jr., in Murray County, Georgia, on Jan. 31, 1992.

Lethal injection is the most common form of execution in the United States, but pentobarbital is not the most controversial element, CNN reported.

Death row inmates nationwide have challenged the use of midazolam in executions.

Mississippi, Oklahoma and Utah allow a firing squad to be used for executions, although lethal injection is the primary method in all three states, according to the Death Penalty Information Center website.

Ledford's lawyers have concentrated on Utah, saying the state has executed three people by firing squad since 1976, most recently in July 2010, CNN reported.

"In Utah's most recent execution by firing squad, the inmate was seated in a chair set up between stacked sandbags to prevent the bullets from ricocheting," his lawyers wrote. "A target was pinned over the inmate's heart. Five shooters set up at a distance of 21 feet from the inmate, armed with .30-caliber Winchester rifles. One rifle was loaded with blanks so that no one knew which officer killed the inmate. The inmate was pronounced dead two minutes after he was shot."

A firing squad has less chance for "operator error" and would reduce Ledford's chance of experiencing severe pain, his lawyers wrote.