More than a month after Hayden Panettiere was found unresponsive inside a South Carolina apartment, authorities have confirmed that the 36-year-old actress died from the toxic effects of fentanyl and several other drugs.
The Greenville County Coroner’s Office determined Panettiere’s death was accidental. Toxicology testing detected fentanyl, 4-ANPP, alprazolam, methocarbamol, and quetiapine in her system. Alprazolam is the generic form of Xanax, methocarbamol is a muscle relaxer, and quetiapine is a prescription medication used to treat conditions including bipolar disorder, schizophrenia, and major depression.
4-ANPP, also known as despropionylfentanyl, is closely associated with fentanyl. Research published in the Journal of Analytical Toxicology describes it as both a precursor used in fentanyl production and a minor fentanyl metabolite that can appear in toxicology testing.
Panettiere died on August 16 while visiting Greenville, South Carolina. According to TMZ, she had traveled from Los Angeles with Brian Hickerson and was later discovered unresponsive inside an apartment by Hickerson and his brother, Zach.
TMZ reported that Hickerson administered Narcan in an attempt to revive her before CPR was performed. Emergency responders continued lifesaving efforts, including chest compressions and advanced cardiac life support, but Panettiere could not be resuscitated. She was pronounced dead at 2:32 p.m.
An initial autopsy found “no signs of trauma” that contributed to her death. Authorities did not initially announce a cause while awaiting toxicology testing.
The official findings now answer one of the biggest questions surrounding Panettiere’s sudden passing, but they may not end the investigation into how the fentanyl reached her.
Nine days after her death, Drug Enforcement Administration agents searched Panettiere’s Los Angeles residence. Federal authorities reportedly obtained a warrant while investigating possible black market controlled substances and searching for evidence that could identify where the drugs came from. Investigators were also reportedly interested in medications and other substances found at the home to determine whether any contained fentanyl.
TMZ previously reported that investigators were examining whether Panettiere may have taken what she believed was an oxycodone pill that instead contained fentanyl. The newly released toxicology findings confirm fentanyl was present in her system, but the coroner’s determination alone does not establish where that fentanyl came from or confirm that a specific pill caused her death. The federal investigation into the circumstances surrounding the drugs has continued.
Investigators have also reportedly been reviewing communications between Panettiere and a suspected drug supplier. Sources told TMZ there were a “slew of messages” discussing drugs, with the correspondence becoming a focus of the DEA investigation.
The circumstances have drawn additional attention to the dangers of counterfeit prescription pills. According to the Centers for Disease Control and Prevention, illegally manufactured fentanyl is frequently pressed into pills designed to resemble medications such as oxycodone and Xanax. Because fentanyl cannot reliably be identified by sight, smell, or taste, people taking counterfeit pills may not know the substance is present.
Fentanyl is a synthetic opioid that can be up to 100 times stronger than morphine. The CDC says illegally manufactured fentanyl remains a major driver of fatal overdoses in the United States. Naloxone, commonly sold under the brand name Narcan, can temporarily reverse an opioid overdose when administered quickly.
Panettiere had previously spoken publicly about her history with alcohol and opioid addiction. She discussed undergoing treatment, managing sobriety, and dealing with postpartum depression following the birth of her daughter, Kaya. In May 2026, she released the memoir “This Is Me: A Reckoning,” which addressed addiction, childhood fame, relationships, motherhood, and the death of her younger brother, Jansen Panettiere, who died in 2023.
Her death came after a career that began when she was still a child. Panettiere appeared in soap operas before becoming recognizable to movie audiences through projects including “Remember the Titans” and “Ice Princess.” She later became one of television’s most recognizable young stars as Claire Bennet on “Heroes.”
She went on to play country singer Juliette Barnes on “Nashville” from 2012 to 2018 and returned to the horror franchise that introduced her character Kirby Reed with “Scream VI.”
Panettiere was remembered by friends and former colleagues during a Malibu memorial gathering on September 19, just days before her official cause of death became public. Connie Britton, Ruby Rose, Charles Esten, and other loved ones were among those who gathered to honor her life and career.
Panettiere is survived by her daughter, Kaya, whom she shared with former fiancé Wladimir Klitschko. She was 36 years old.
