Fentanyl Deaths Start to Fall — and Carfentanil Returns, 2021–2024

In 2013, illegally manufactured fentanyls (IMFs) — fentanyl and its illegal analogs — began turning up in the U.S. drug supply, mixed into or replacing white-powder heroin in the Northeast. They have since replaced heroin as the country's dominant opioid, and because they are so potent and act so fast, overdose deaths rose sharply. In 2023, about 72,000 overdose deaths — nearly seven in ten — were estimated to involve fentanyl.

Provisional data showed the first decline in overdose deaths since 2018 in 2023, continuing into 2024. But carfentanil, a fentanyl analog 100 times more potent than fentanyl, which had largely vanished after outbreaks in 2016–2017, was coming back. CDC used its State Unintentional Drug Overdose Reporting System (SUDORS) — death certificates, medical examiner and coroner reports, and toxicology — to track both.

Fentanyls: deaths turn down

In 46 jurisdictions (45 states and the District of Columbia), 251,089 overdose deaths occurred in 2021–2023, and IMFs were found in 188,082 (74.9%).

Within 2023 the turn is clear: deaths with IMFs peaked in April–June at 16,814, fell 4.7% to 16,019 in July–September and another 11.2% to 14,229 in October–December. The second half of 2023 was 7.8% below the second half of 2022. Overdose deaths overall followed the same path.

Figure 1. Overdose deaths overall and with IMFs detected, by quarter, 2021–mid-2024. CDC

By region: the West is different

In the West, deaths with IMFs rose 19.5% from 2021 (5,949) to 2022 and 60.1% from 2021 to 2023, before falling 13.0% late in 2023 (2,588 in July–September to 2,252 in October–December). Fentanyl reached Western markets later, probably because it was hard to mix into the black tar heroin common there; counterfeit pills containing IMFs have since helped it spread.

Figure 2. The same measures by Census region. CDC

Why deaths may be leveling off

Where IMFs have made up 70–80% of overdose deaths for years — the Northeast, Midwest and South — the supply appears saturated: fentanyl is the dominant illegal opioid, at a stable level. The authors suggest several reasons that could lower risk:

• people who use drugs may have higher tolerance, and may know their drugs contain fentanyl;
• non-opioid drugs such as xylazine mixed into the supply may lower fentanyl purity;
• more people may survive long enough to benefit from prevention programs — naloxone distribution and better access to treatment.

If the West behaves like the other regions, where deaths plateaued once 70% or more involved IMFs, it too may soon level off.

Carfentanil: rare, but spreading fast

Carfentanil was found in 513 overdose deaths from January 2021 to June 2024 — very few until mid-2023.

From the first half of 2023 to the first half of 2024 that is an increase of 720.7%. The average went from 3.3 deaths a month (January 2021–June 2023) to 34.4 a month (July 2023–June 2024).

This return looks unlike 2016–2017:

That suggests carfentanil is being mixed into fentanyl products, perhaps without users knowing — much as fentanyl first arrived hidden in heroin. Other opioids stronger than fentanyl, such as some nitazenes, are rare but persistent in overdose deaths and also need close watching.

Figure 3. Deaths with carfentanil detected, by half-year and by state. CDC

What helps

Because carfentanil is a fentanyl analog, efforts aimed at IMFs work against it too:

• education about the risks of drug use, and of pills that were not prescribed — they may be counterfeit and contain IMFs;
• drug checking services, so people know what their drugs contain;
• wider access to naloxone, for people who use drugs and for bystanders, to reverse overdoses in time — though carfentanil may need more doses and a faster response;
• advice such as not using alone;
• fentanyl test strips — which detect fentanyl but cannot tell carfentanil from fentanyl.

Combined with preventing people from starting drug use and widening access to treatment, including medications for opioid use disorder, these could bring lasting declines able to withstand changes in the drug supply.

Limits

1. Only 46 or 50 jurisdictions were included, depending on the analysis.
2. Postmortem toxicology testing is not standardized, so carfentanil may be detected unevenly.
3. 2024 data are preliminary; not all deaths had been reported.

All of these likely mean the rise in carfentanil deaths is larger than reported here.

Sources

Based on Tanz LJ, Stewart A, Gladden RM, Ko JY, Owens L, O'Donnell J, "Detection of Illegally Manufactured Fentanyls and Carfentanil in Drug Overdose Deaths — United States, 2021–2024," MMWR Morbidity and Mortality Weekly Report volume 73, number 48, Centers for Disease Control and Prevention; a work of the United States government in the public domain.