WASHINGTON: The female inmate who survived a failed execution in a US prison last week is now conscious and speaking, but her prognosis remains unclear, her lawyers said Tuesday.

Christa Pike, 50, who was sentenced to death for a murder she committed when she was a teenager, received two supposedly lethal doses of the drug pentobarbital at a Tennessee prison a week ago.

She survived the injections, however, and was rushed to hospital, where she had been unconscious and on a ventilator in critical condition.

Pike's lawyers said that "against all odds" she was now "conscious, speaking, and continues to receive critical medical care."

"Despite the severe damage she endured to her arms, she is still handcuffed and shackled to the bed," they said. "Her recovery is medically unprecedented. Her prognosis remains unclear but, at a minimum, we expect a long recovery."