Health officials are warning residents about carfentanil, a deadly opioid that has reemerged and contributed to 11 overdose deaths in Michigan this year.
Carfentanil is a synthetic opioid that is 100 times more potent than fentanyl. It was created for veterinary use with large animals and isn’t approved for use in humans, according to the Michigan Department of Health and Human Services.
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The opioid was previously seen in Michigan in 2016 and 2017. It contributed to 107 deaths in 2016 and 111 deaths in 2017.
Over the following years, deaths associated with carfentanil dropped to less than five per year, and were at zero in 2021 and 2022, before rising to 14 in 2023.
Now, health officials say between January and June 2025, 11 deaths involved carfentanil in Michigan.
The reported deaths happened in Eaton, Genesee, Ingham, Livingston, Oakland and Wayne counties.
None of the deaths involved carfentanil alone, according to the health department. Ten of the people who died also tested positive for cocaine, and fentanyl was identified in eight of the deaths.
Health officials say this reemergence is concerning because people who use these drugs and other stimulants may not be aware that they could contain carfentanil.
Carfentanil could also lead to more overdoses due to its higher strength, and it may also require additional doses of naloxone due to its strength.
It also concerns health officials because it “quickly causes central nervous system depression, which can lead to rapid death,” according to the MDHHS.
“Carfentanil is an extremely potent and deadly drug,” said Dr. Natasha Bagdasarian, chief medical executive. “We’re urging people who use unregulated drugs – and their loved ones – to carry naloxone, an easy to administer nasal spray that can reverse opioid overdoses and save lives. Awareness and quick action can help save lives.”
Residents can request naloxone through the MDHHS or through a pharmacy.