The Tennessee Supreme Court on Tuesday upheld the state’s lethal injection protocol over a challenge by several death row inmates who argued the three-drug injection inflicted unnecessary pain.

In July the Tennessee Department of Corrections revised the protocol to eliminate pentobarbital, providing for a three-drug injection now including midazolam to provide pain relief.

The 33 inmates that filed the complaint have each been sentenced to death in Tennessee, with three scheduled for execution in 2018. They assert that the eliminated drug pentobarbital offered a quicker and less painful method for execution, making the revisions cruel and unusual under both the US and Tennessee Constitutions.

In the ruling, the court clarified that the claimants did not meet the burden established by the Supreme Court in 2015 in Glossip v. Gross in which they had to prove an available alternative. The court also found that the facts do not violate the constitution as to constitute torture or deliberate infliction of pain.