Carfentanil; A New Drug in America that’s 100 Times More Potent than Fentanyl

Paramedics working at night
Photo by MattGush/

A recent front-page news story in USA Today revealed that two California residents were just arrested for possessing-with-intent-to-distribute 46 lbs of carfentanil. Carfentanil, a large animal tranquilizer drug, was never intended for human consumption, and previous cases of human misuse of the drug were few and far between. But given that a pair of drug traffickers were just arrested in possession of enough carfentanil to kill millions of people, the alarm bells of carfentanil drug trafficking are finally ringing.

What is Carfentanil?

Carfentanil is not a new drug. It is not approved for human use and is only used to immobilize large exotic animals for veterinary purposes. However, its consumption by humans is relatively new. According to the Journal of Analytical Toxicology, “Carfentanil is a… opioid receptor agonist and is estimated to be ~10,000 times more potent than morphine in animal (non-human) models. In mid-2016, carfentanil emerged as a contaminant in street heroin in the USA and was central to a large number of emergency department visits and deaths.”

Drugs involved in US overdose deaths chart
Drugs Involved in U.S. Overdose Deaths* – Among the more than 64,000 drug overdose deaths estimated in 2016, the sharpest increase occurred among deaths related to Fentanyl and Fentanyl Analogs (synthetic opioids) with over 20,000 overdose deaths. Source: CDC WONDER

Premier Biotech put together a concise analysis of the different types of fentanyl analogs, comparing the potency of the different types of opioid substances. (An analog is simply a drug that has similar physical properties to another drug). Premier Biotech published this definition of carfentanil, also showing its unique chemical properties, “A potent synthetic opioid that has been used as an elephant tranquilizer. It is 100 times more potent than Fentanyl, and 10,000 times more potent than morphine. An amount smaller than a few grains of salt can be a lethal dose.” At the time of this writing, carfentanil is the most potent opioid drug being used in America, so potent in fact that even just getting some carfentanil on one’s exposed skin can lead to an overdose.

Clearly, carfentanil is an extremely potent opioid, thousands of times more potent than morphine, several hundred times more potent than heroin, and about 100 times more potent than fentanyl. Given that carfentanil was intended for large animal tranquilization and was never intended for human consumption, an introduction of carfentanil into an illicit opioid supply could result in a surge of drug overdose deaths.

The California Carfentanil Trafficking Arrest

California police car

On September 26th, 2021, a story appeared in USA Today, detailing the arrest of two southern California residents who had more than 46 lbs of carfentanil in their possession. Though the investigation is still ongoing, it’s believed that the drug traffickers intended to mix the carfentanil with other opioid drugs to increase potency, as it is virtually impossible to use carfentanil by itself without inducing an overdose.

At this time, it is believed that the recent Riverside County case out of California is the largest seizure of carfentanil in U.S. history, dwarfing a 2019 New York law enforcement seizure of 11 lbs of carfentanil.

Past Cases of Carfentanil Misuse and Overdose: Analyzing the Data

The Centers for Disease Control and Prevention has carefully documented cases of carfentanil overdose and death. According to CDC authors, “It [carfentanil] has recently been reported in an alarming number of deaths in some states. Ohio reported nearly 400 carfentanil-involved deaths during July–December 2016, and Florida reported >500 such deaths for all of 2016.” Later in their report, the authors said, “During July 2016–June 2017, among 11,045 opioid overdose deaths, 2,275 (20.6%) decedents tested positive for any fentanyl analog, and 1,236 (11.2%) tested positive for carfentanil.”

Another CDC report examined Florida carfentanil cases, reporting on a surge of carfentanil-related deaths in that state over a relatively short period of time. Quoting that group of CDC researchers, “During January 2016–December 2017, 224 of Florida’s 1,181 carfentanil-involved fatal overdoses occurred in the Sarasota area, preceding a larger statewide outbreak in the rest of the state. The outbreak ended in the Sarasota area in August 2017, but carfentanil continued to be detected in overdose deaths in other areas of Florida through the end of 2017.” From the CDC reports, it seems that when carfentanil appears in an urban area, a slew of overdose deaths soon follow.

The National Institute on Drug Abuse and the Drug Enforcement Administration picked up where the CDC left off, releasing their own warnings about the rising threat of carfentanil misuse. Both organizations also raised awareness of climbing cases of carfentanil-related deaths.

“As with many fentanyl analogs, it is likely that carfentanil is being added to mixtures of heroin and other street drugs...”

NIDA and DEA officials have suggested that drug traffickers were mixing carfentanil in with other opioid drugs to increase potency. Authorities have not officially announced this yet, but it’s very likely the 46 lbs of seized carfentanil in California was intended for this type of use; i.e., mixing it with other drugs to increase potency and lethality. And given official reports from NIDA, it’s safe to say that the prediction on the 46 lbs of carfentanil being intended for mixture into other drugs was more than just speculation. From the National Institute on Drug Abuse, “As with many fentanyl analogs, it is likely that carfentanil is being added to mixtures of heroin and other street drugs, but it is not known how often carfentanil is being added to or substituted for other opioids in street drugs, underscoring its danger.”

If drug traffickers see a clear profit incentive in increasing the potency of their opioid drugs by adding carfentanil to them, opioid users in the U.S. are at even greater risk for overdoses and death.

Opioid Addiction Treatment; Avoiding an Overdose and Walking Away from Drugs for Life

Helping an addict

The recent carfentanil drug bust is a warning sign of growing interest in carfentanil among drug dealers and users. And even for those users who want nothing to do with carfentanil, how can they be sure their opioid supply does not have carfentanil in it?

The growing cases of carfentanil trafficking and misuse must act as a clear warning sign to parents and families of opioid addicts. Carfentanil is truly lethal for even the most opioid-tolerant users. The only way to safely ensure that an opioid addict will not accidentally use carfentanil and overdose on the substance is to get them into a residential drug treatment center as soon as possible. Such programs possess the tools and resources to help a loved one overcome the underlying crises and struggles that led them to misuse opioids in the first place, thus freeing them from the dwindling spiral and potentially lethal trap that is opioid addiction.

If you or someone you know is addicted to opioids, please contact a qualified residential drug treatment center today. Please don't wait until it is too late.


Reviewed by Claire Pinelli ICAADC, CCS, LADC, RAS, MCAP, LCDC



After working in addiction treatment for several years, Ren now travels the country, studying drug trends and writing about addiction in our society. Ren is focused on using his skill as an author and counselor to promote recovery and effective solutions to the drug crisis. Connect with Ren on LinkedIn.