What is Narcan, the substance found at the scene where Hayden Panettiere died? This is what it’s used for

The circumstances surrounding Hayden Panettiere ’s death have brought renewed attention to Narcan, a medication that was reportedly present at the South Carolina property where the actress was found unconscious.

Panettiere, known for her roles in Heroes and Nashville, died at 36 after emergency responders were called to a Greenville residence on Sunday.

Her death remains under investigation, and authorities have not announced an official cause. An autopsy reportedly found no signs of trauma, while investigators have continued examining the circumstances surrounding her death.

New information from Brian Hickerson ’s brother, Zach Hickerson, has provided additional detail about what happened before emergency crews arrived.

Zach said Brian administered Narcan after the brothers found Panettiere unconscious.

"Brian gave her Narcan,” Zach said to TMZ. Zach later described the emergency response in greater detail, saying: "I immediately called 911 and Brian gave her Narcan. We then jointly performed CPR while 911 was on speaker until Fire and EMS arrived. At that point we watched as they tried every measure possible to save her life."

His account is significant because TMZ had previously reported that Narcan was found at the property, although it was initially unclear who had administered it or who had received the medication.

What exactly is Narcan and how does it work?

Narcan is a brand name for naloxone, a medication designed to rapidly reverse the effects of an opioid overdose.

Naloxone works by blocking opioid receptors in the brain. During an opioid overdose, drugs such as fentanyl, heroin, oxycodone, hydrocodone or morphine can suppress the body's ability to breathe. Naloxone can temporarily displace those opioids from their receptors, potentially restoring normal breathing.

It is particularly important to understand that Narcan is not an intoxicating drug and is not itself an opioid. The FDA describes naloxone as an emergency treatment that can be administered by people without medical training when an opioid overdose is suspected.

Narcan became much more accessible in the United States after the FDA approved a 4 mg nasal-spray version for over-the-counter use in March 2023. That decision allowed consumers to obtain the medication without a prescription, including through pharmacies and other retail outlets.

The medicine is intended for emergencies. If someone is suspected of overdosing, naloxone should be administered while emergency medical assistance is sought.

Its effects are temporary, meaning a person can become unconscious again after the medication wears off. The FDA says repeat doses may sometimes be necessary.

That point is important in understanding the circumstances reported at Panettiere’s home. The presence or use of Narcan does not, by itself, establish that someone died from an opioid overdose. Only investigators and medical authorities determining the cause of death can establish what happened.

Panettiere had previously spoken publicly about addiction and her struggles with alcohol and substance use. In her 2026 memoir This Is Me, she discussed those experiences alongside other difficult periods in her life.

Her death has now prompted a broader investigation. TMZ has reported that the Drug Enforcement Administration has become involved, while local authorities continue examining the circumstances.

Zach has also pushed back against speculation surrounding Panettiere’s death: "There are a lot of assumptions, speculations and accusations currently swirling. The truth will come out as the authorities complete and release additional details from the investigation. And that is important because the people who loved and adored Hayden deserve the truth."

He added: "Out of respect for her loved ones, the speculation and sensationalism of her death needs to end until the facts can be released from the investigation."

As investigators work to establish what happened, the reported use of Narcan is one piece of a much larger picture. The medication is specifically designed to save lives during suspected opioid overdoses, but its presence at a scene cannot substitute for a medical determination of the cause of death.

For now, Panettiere’s cause of death remains officially unresolved, and authorities are expected to rely on toxicology, medical evidence, witness accounts and other investigative findings before reaching a final conclusion.