Why we need to worry about the re-emergence of carfentanil

Carfentanil is gaining attention once again in the United States. Officially used as a tranquilizer for large animals, like elephants and moose, carfentanil has also appeared in the street drug supply. It is 100 times more potent than fentanyl and 10,000 times more potent than morphine—so using carfentanil carries a significant risk of overdose¹. The drug is not approved for human use.

Previously, removing carfentanil from the drug supply through law enforcement drug seizures had reduced overdose deaths. But now it’s re-emerging in the drug supply, leading officials and communities to worry about the implications for public health. 

What is carfentanil?

Carfentanil is a synthetic opioid and analog of fentanyl that was first synthesized in the 1970s. Unlike fentanyl, there are no approved medical uses of carfentanil for humans. It is approved exclusively for veterinary uses with large animals. However, illegal carfentanil appears in counterfeit pills and contaminated cocaine and heroin in the street drug supply. 

Carfentanil vs. fentanyl

As an analog, carfentanil has a lot in common with fentanyl. They are both potent synthetic opioids. Carfentanil is much more potent, however, and not approved for any human use. Fentanyl, on the other hand, is approved by the U.S. Food and Drug Administration (FDA) to treat severe pain². 

Despite being the less potent of these two drugs, fentanyl has been the primary driver of the rise in overdose deaths involving synthetic opioids, not carfentanil³. This is likely because fentanyl is much more prevalent in the drug supply.

History of carfentanil in the U.S.

Carfentanil first entered the illegal drug supply in the U.S. in 2013, around the same time fentanyl was gaining traction. Introducing these drugs, also known as illegally manufactured fentanyl and fentanyl analogs (IMFs), led to a significant increase in opioid overdose deaths⁴.  

By 2016, carfentanil was reported in “an alarming number of deaths” in some states⁵. Florida, Michigan, and Ohio reported some of the first fatal opioid overdoses involving carfentanil in the United States. Between January 2016 and December 2017, there were over 1,000 carfentanil deaths in Florida alone⁶. Deaths involving fentanyl analogs like carfentanil nearly doubled between the second half of 2016 and the first half of 2017 in the United States⁵.

After these carfentanil overdose death outbreaks in 2016 and 2017, however, the drug largely disappeared from the drug supply⁴. Overdose deaths declined in 2018 from 21.7 per 100,000 the previous year to 20.7, a 4.6% decrease. The law enforcement response that helped remove carfentanil from the drug supply likely contributed to this decrease. 

Carfentanil’s recent return to the U.S. drug supply

Recently, carfentanil has re-emerged in the U.S. illicit drug supply, prompting concern. Though carfentanil overdose deaths were rare, they increased by over 700% when comparing January to June 2023 to the same period in 2024⁴. This spike in carfentanil overdose deaths highlights the constant changes in the illegal drug supply in the U.S.  

Compared to the 2016–2017 localized outbreaks of fatal carfentanil overdoses, the current carfentanil overdose deaths are much more widespread. Thirty-seven states reported overdose deaths with carfentanil detected in the first half of 2024⁴.

Carfentanil is generally produced outside the U.S. and then smuggled into the country, much like fentanyl. Authorities in Mexico have dismantled some carfentanil pill mining operations, and Chinese officials closed some loopholes by adding controls on fentanyl-related substances like carfentanil, but the drug has still popped back up in the drug supply⁹. The carfentanil problem is truly international, making it that much more difficult to counter.

Harm reduction and carfentanil

Drug overdose deaths fell overall by 14.5% between June 2023 and June 2024, but the re-emergence of carfentanil could “threaten this progress,” according to the CDC⁴. Given the potency and reappearance of carfentanil, opioid overdose prevention efforts will now need to adapt quickly to address these evolving concerns. 

Addressing the threat of opioid overdose requires several prevention efforts, including:

• Further increasing access to naloxone, a drug that rapidly reverses the effects of opioid overdoses, to ensure the availability of sufficient doses for more potent drugs
• Educating about the risks of using illicit drugs that may contain fentanyl or carfentanil
• Making fentanyl test strips more readily available
• Expanding access to programs that provide medications for opioid use disorder (MOUD)

Though test strips won’t distinguish between fentanyl and carfentanil, they do allow people using drugs to make more informed decisions⁴.

Expanding access to opioid use disorder (OUD) treatment is also essential in the effort to reduce opioid overdose deaths, including carfentanil overdoses. Ophelia is dedicated to helping people with OUD access the care they need with telehealth treatment. Explore your treatment options today.