The inmate who survived a botched execution in the US is now awake and talking, almost a week after being injected with two lethal doses of a barbiturate.

Christa Pike was left unconscious and on a ventilator six days ago after executioners in Tennessee attempted to end her life for the killing of a classmate 31 years ago.

The execution attempt, in which she was injected with an initial and backup dose of pentobarbital, lasted more than an hour before she was taken to hospital.

Her lawyers told the media that Ms Pike had thrombocytosis, which may have made it difficult to get needles into her veins, and that one of several needles used appeared to be bent after it was pulled from her arm.