Tennessee suspended executions for the rest of 2026 on Thursday after Christa Pike survived two pentobarbital injections administered hours apart in an attempt to put her to death on Wednesday night.

Ms. Pike, 50, the only woman on Tennessee’s death row, remained in critical condition and was receiving life-saving care at a hospital in Nashville, her lawyers said on Thursday. They did not know her prognosis.

The procedure at Riverbend Maximum Security Institution went forward after the U.S. Supreme Court lifted a temporary stay imposed by a federal appeals court at roughly 6 p.m. Ms. Pike was convicted of killing Colleen Slemmer, a 19-year-old classmate, in January 1995, when Ms. Pike was 18. She had spent 30 years on death row and never denied her role in the crime.

Ms. Pike would have been the first woman Tennessee had executed since 1820 and the 19th woman put to death in the United States since 1976. On Monday, Gov. Bill Lee had rejected her request to commute the sentence to life in prison.

The execution team spent about an hour trying to place intravenous lines, using at least seven needles in Ms. Pike’s left arm, one of which was bent when it was removed, said Randall Spivey, one of her lawyers and a witness to the attempt. Ms. Pike, who has a lifelong blood disorder and difficult veins, helped guide the staff. “Please try here, please try here,” Mr. Spivey recalled her saying. “She told them over and over, please try higher on my shoulder.”

After the first dose, Ms. Pike complained of a burning sensation and said her arm felt as if it was “about to burst open,” according to media witnesses. She moaned, kicked off a sheet and asked whether her arm was supposed to feel that way. Her right arm turned purple and the injection sites blistered and burned, her lawyers said.

Prison officials briefly closed the observation curtains at 7:46 p.m. and closed them for a final time at 8:05. The attempt was abandoned about 8:25 p.m., though witnesses could still hear Ms. Pike snoring when the chamber’s microphone was cut at 8:53. An ambulance took her from the prison.

Mr. Spivey said he did not see emergency treatment before she left the chamber. Speaking at a news conference Thursday, he called the attempt “cruel and torturous” and renewed the legal team’s request for clemency. “Christa is alive right now,” he said. “We don’t have a sense of her prognosis or much update on her health at the moment, but we do know that she is alive right now.”

The Death Penalty Information Center said Ms. Pike appeared to be the first person known to survive after execution drugs entered her body. Robin Maher, the group’s executive director, called the attempt “the worst we’ve ever seen and unlike any other botched execution in the modern era.” Earlier failures generally involved execution teams that could not place an intravenous line.

Ms. Pike’s lawyers and several doctors said her symptoms suggested that at least some of the pentobarbital entered the surrounding tissue rather than her bloodstream. Dr. Jonathan Groner, an emeritus professor of clinical surgery at Ohio State University, told NBC News that such an infiltration would have left too little of the drug circulating to stop her breathing. Dr. Joel Zivot, a professor at Emory University’s medical school retained by the defense, told the BBC that delayed resuscitation could have caused a brain injury.

The Tennessee Department of Correction said in a statement that it “followed every step of the State’s lawful, established execution protocol” and that pentobarbital “has consistently been effective.” Tennessee adopted the single-drug method in 2024. Because European law bars pharmaceutical companies from selling drugs for executions, states typically obtain them from small compounding pharmacies through confidential arrangements.

Mr. Lee, a Republican, said the failure was “deeply disturbing” and ordered a third-party review, but said it appeared that prison staff had followed procedure. “There is no one that wanted what happened last night to happen,” he said. “It’s a tragedy, and it’s deeply disturbing to me that that has happened in this state.”

The governor postponed Ms. Pike’s execution indefinitely and halted Tennessee’s only other planned 2026 execution, that of Gary Wayne Sutton on Dec. 3. In May, the state called off its attempt to execute Tony Carruthers after working for more than an hour to find a vein and piercing him with needles and a scalpel, in an account by The Atlantic.

There is no automatic constitutional prohibition on carrying out Ms. Pike’s sentence again if investigators decide that officials followed procedure and did not violate her Eighth Amendment rights, according to The Independent’s review of the legal question. In the meantime, State Senator Marsha Blackburn, the Republican nominee for governor, called for Tennessee to return to the electric chair, while Cameron Sexton, the Republican House speaker, said lawmakers would consider new drugs, including potassium chloride.

May Martinez, Ms. Slemmer’s mother, traveled to Nashville to witness the execution and told NBC News afterward, “It was a mess.” Stephen Ferrell, another of Ms. Pike’s lawyers, said her greatest concern had not been death itself but the manner of it. “It was a fear of a prolonged, painful, traumatic death,” he said, “and that’s what happened minus the death.”