Michael Graczyk reports for AP:

A Texas man convicted of killing a 38-year-old woman nearly two decades ago while he was on parole for a triple slaying years earlier was executed Thursday evening.

Robert Ladd, 57, received a lethal injection after the U.S. Supreme Court rejected arguments he was mentally impaired and ineligible for the death penalty. The court also rejected an appeal in which Ladd's attorney challenged whether the pentobarbital Texas uses in executions is potent enough to not cause unconstitutional pain and suffering.

There are no dissents noted in the two Supreme Court orders.  Pentobarbital is the way to go.