Actress Hayden Panettiere died from the toxic effects of fentanyl and several other substances, according to findings released Tuesday by the Greenville County Coroner’s Office.
The “Heroes” and “Nashville” star was 36 when she was found unresponsive inside a Greenville, South Carolina, residence on Aug. 16.
Authorities classified Panettiere’s death as an accident, providing the first official determination of what caused her sudden death more than one month earlier.
The coroner listed fentanyl, 4-ANPP, alprazolam, methocarbamol and quetiapine as contributing to the fatal toxic effects.
Alprazolam is commonly sold under the brand name Xanax and is used to treat anxiety and panic disorders. Methocarbamol is a muscle relaxant, while quetiapine is prescribed for several mental health conditions.
The substance 4-ANPP is associated with fentanyl production and can also appear as a fentanyl byproduct.
Emergency dispatchers received a 911 call reporting a cardiac arrest at approximately 1:51 p.m. on Aug. 16.
First responders found Panettiere in cardiac arrest and began advanced life-support measures. Their efforts were unsuccessful, and she was pronounced dead at 2:32 p.m.
An autopsy conducted by a board-certified forensic pathologist found no evidence of trauma that contributed to her death, according to the coroner.
Authorities previously said the initial investigation uncovered no evidence of foul play or suspicious circumstances.
Although the coroner’s office has established the cause and manner of Panettiere’s death, Greenville police said their broader investigation remains active.
Kasey Kitchen, a publicist representing Panettiere’s family, described the case as complex and confirmed that investigators were continuing their work.
Federal authorities have also reportedly investigated the possible source of the fentanyl found in Panettiere’s system, including whether it originated in California or South Carolina.
Panettiere had previously spoken publicly about her struggles with alcohol and opioid addiction, as well as postpartum depression following the birth of her daughter, Kaya.
She discussed those experiences and the pressures of childhood fame in her memoir, “This Is Me: A Reckoning,” which was released earlier in 2026.
Panettiere began acting as a child, appearing in commercials and soap operas before earning increasingly prominent film and television roles.
She gained widespread recognition portraying Sheryl Yoast in the 2000 football drama “Remember the Titans.”
Her career reached another level when she played cheerleader Claire Bennet on the NBC superhero series “Heroes.” Her character became closely associated with the show’s “Save the cheerleader, save the world” storyline, according to Trending Politics.
Panettiere later portrayed country music star Juliette Barnes on ABC’s “Nashville” opposite Connie Britton. The role earned her two Golden Globe nominations.
Her other credits included “Scream 4,” “Scream VI,” “Racing Stripes,” “Ice Princess” and the animated film “A Bug’s Life.”
Panettiere died five days before what would have been her 37th birthday.
Her father, Skip Panettiere, remembered his daughter as “an incredible light and a force of nature” who brought joy to her family and audiences.
Panettiere is survived by Kaya, whom she shared with former heavyweight boxing champion Wladimir Klitschko.
