New Strain of Fentanyl Is Resistant to Our Only Overdose Antidote

The opioid epidemic continues to tighten its grip on the US and now authorities are warning about two new strains of fentanyl—the synthetic opioid that's 50 to 100 times more powerful than morphine—that are showing resistance to the life-saving overdose antidote. One strain can be even more potent than regular fentanyl.

According to a recent news release from the Georgia Bureau of Investigation Crime Lab, the two new fentanyl analogues—acrylfentanyl and tetrahydrofuran fentanyl—were identified by the lab after a drug seizure by the Forsyth County Sheriff's office in March. The sheriff seized the drugs when EMTs responded to four opioid overdoses in one weekend; two of them were fatal.

But their deadly effects don't result from ingestion alone; both drugs can be absorbed through the skin, making them even more dangerous. The drugs aren't intended for human or veterinary use—unlike fentanyl and carfentanil, respectively—so it's still unknown how the human body will react to them, per the release, or exactly how strong they are. But according to multiple reports from other states also dealing with the strains, the opioid overdose-reversal drug naloxone (brand name Narcan) may not be effective against an acrylfentanyl overdose.

Neither drug had been previously identified by the GBI crime lab, though acrylfentanyl had been on the bureau's watch list for the past few months; it became illegal in the state in April. And in late May, the Drug Enforcement Administration temporarily added acrylfentanyl to its Schedule 1 list of controlled substances, rendering it illegal nationwide. Meanwhile, tetrahydrofuran fentanyl is still so new that it's not currently listed on the DEA's list of banned substances, nor is it covered by Georgia law—meaning it's not yet illegal to sell or buy the drug.

And it's not just Georgia; acrylfentanyl has also popped up in Cook County, Illinois, causing 44 overdose deaths this year alone, as well as in Western Pennsylvania, where it caused two overdose deaths in two separate counties, per a CBS affiliate in Pittsburgh. The DEA says it's been linked to 31 deaths in Ohio and 22 in Maryland. Steve Aks, an emergency medicine physician at Chicago's Stroger Hospital, said in a statement in May: "In many cases, one dose of naloxone, the heroin antidote, will revive a person who has overdosed on heroin. But we are seeing people in our emergency department who need increased doses of naloxone—in some cases as many as four doses—for the patient to be stabilized after ingesting fentanyl, or a heroin/fentanyl combination." The Cook County medical examiner warned that just one dose of fentanyl or acrylfentanyl could kill people by halting their breathing.

Nationwide, the death rate from synthetic opioids jumped more than 72 percent from 2014 to 2015; the latest data from the Centers for Disease Control—likely due to illicitly-manufactured fentanyl, not the prescribed drug.

According to the DEA, the new designer drugs are likely manufactured in China, Canada, and Mexico, and then smuggled into the US and sold online. The drugs come in powder form, making them look so similar to fentanyl, carfentanil, and even heroin, that even narcotics experts can't tell the difference with the naked eye.

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