Public Health Officials Confirm First Fatal Carfentanil Overdose in Riverside County Resident
Thursday, July 17
The synthetic opioid is 100 times more potent than fentanyl.
RIVERSIDE, CA - (July 17, 2025) A Riverside County resident has been confirmed to have died as a result of a carfentanil overdose – a synthetic opioid that Riverside University Health System – Public Health (RUHS-PH) officials say is 100 times stronger than fentanyl and 10,000 times more potent than morphine.
The death – a male in his 40s – occurred in March 2025, outside Riverside County. It can take months to confirm the cause of death, particularly if it occurs outside of county.
"Every life lost from opioids is one too many. Together, we can continue to raise awareness about the risks associated with drug use and work as a community to support safety, reduce harm and care for one another," said Riverside County Public Health Officer Dr. Jennifer Chevinsky.
Carfentanil was developed for use as a tranquilizer in large animals, such as elephants, and due to its potency, even a minuscule amount can cause a fatal overdose, Dr. Chevinsky added.
According to a Centers for Disease Control and Prevention (CDC) report, illegally manufactured fentanyls (IMFs) first entered the illegal drug supply in the United States in 2013 as a substitute for white powder heroin in the Northeast. Although rare, U.S. deaths with carfentanil detected increased approximately sevenfold, from 2 deaths in the first six months of 2023 to 14 deaths counting the same period in 2024. IMFs were responsible for roughly 70% of overdose deaths in the United States in 2023, the report said.
Despite the rise in IMFs, there has been success nationally and locally with opioid overdose deaths declining. Riverside County experienced a 25% decrease in overdose deaths in 2024. The use of naloxone (Narcan), the life-saving antidote that can sometimes revive individuals who have overdosed, and an increase in public awareness and action are among the contributing factors for the decrease.
"While overall we are seeing a decrease in opioid overdose deaths in Riverside County, this is a reminder that there are things each of us can do to prevent these terrible outcomes. Everyone deserves dignity, compassion and the opportunity to be safe," Dr. Chevinsky said.
RUHS-PH suggests residents:
- Carry naloxone. It is available without a prescription in many pharmacies and at local public health offices. Free training and kits are available through the department.
- Share resources. Never Use Alone, the U.S. National Overdose Response line (800.484.3731), is a helpline available to individuals who are using substances by themselves. Volunteer operators take down location information, and alert EMS to that location if there is no response after using.
- Offer help. Individuals struggling with substance use may call 800.662.HELP for help quitting.
Because of the unpredictability and potency, using small amounts and spacing out doses does not guarantee safety. Fentanyl strips can provide some information on a drug's contamination and risk but may not detect carfentanil.
Public Health collaborates with harm reduction organizations, local emergency responders and community partners to increase access to life-saving tools and education. RUHS-PH hosts California's first Overdose Fatality Review and participates in the Riverside County Fentanyl Multidisciplinary Committee.
