Ohio says it's resuming executions in January with a three-drug protocol similar to one it used for several years.

The concept is one adopted for decades by many states: the first drug sedates inmates, the second paralyzes them, and the third stops their hearts.

The key difference comes with the first drug the state plans to use, midazolam, which has been challenged in court as unreliable.

The state argues that a planned dose of 500 milligrams will ensure that inmates are properly sedated.

Defense attorneys say it's unclear what a much bigger dose would achieve.

Last year, the U.S. Supreme Court ruled 5-4 that midazolam can be used in executions without violating the Eighth Amendment prohibition on cruel and unusual punishment.