A drug used to sedate elephants and other large animals, 100 times as potent as the fentanyl already escalating the country's heroin troubles, is suspected in spates of overdoses in several states, where authorities say they've found it mixed with or passed off as heroin.
The appearance of carfentanil, one of the most potent opioids known to investigators, adds another twist to the fight against opioid painkillers in a country already awash in heroin and fentanyl cases.
"It certainly is a very disturbing trend," Ohio Attorney General Mike DeWine said.
A man suspected of selling carfentanil as heroin was indicted this week in central Ohio on 20 counts, including murder, in connection with a July 10 death and nine other overdoses that happened within hours of one another. Some of the surviving users told investigators they thought they were buying heroin, but testing found none, Franklin County Prosecutor Ron O'Brien said. The suspect, 36-year-old Rayshon Alexander, pleaded not guilty.
Investigators are still trying to track down the source of the carfentanil. DeWine said he wasn't aware of any thefts of the drug, which, he noted, could be shipped from abroad or produced here.
Chinese companies sell carfentanil online, but it hasn't shown up much in the U.S. drug supply, according to the U.S. Drug Enforcement Administration. There hasn't been much evidence of carfentanil on the streets or in testing related to criminal cases, said agent Rich Isaacson, a spokesman for the DEA's Detroit Division, which covers Ohio.
The drug has been suspected in overdoses or found in seized drugs in central Kentucky and in Florida's Tampa Bay and Sarasota areas, as well as other Ohio cities. Akron authorities have seen over 230 overdoses in July, 20 of them fatal, and police said evidence of carfentanil was found in some of those.
Carfentanil is thought to be similar in strength to a painkiller known as W-18, which has shown up in heroin in Philadelphia, New England and Canada.
Carfentanil is so powerful that zoo veterinarians typically wear a face shield, gloves and other protective gear - "just a little bit short of a hazmat suit" -- when preparing the medicine to sedate animals because even one drop splattered into a person's eye or nose could be fatal, said Dr. Rob Hilsenroth, executive director of the American Association of Zoo Veterinarians.
A loaded syringe of a reversal drug is kept on hand just in case, and the extremely limited carfentanil supply regulators allow for such facilities is kept locked away and subject to auditing, Hilsenroth said.
Investigators are taking the risks seriously. In a bulletin to law enforcement agencies last week, DeWine's office discouraged police from field-testing suspected heroin or fentanyl for fear that it contains carfentanil or other potentially harmful synthetic opioids. Instead, the office recommended sending samples straight to a lab for testing.
DeWine said drugs used for animals have showed up in street drugs before, but carfentanil is so new on the investigative scene that the state's crime lab didn't even have a standard for comparing samples.
In some suspected carfentanil cases, emergency responders have had to administer multiple doses of the overdose antidote naloxone - often known by the brand name Narcan - to save people, but even the antidote might not be enough.
Dr. Lakshmi Sammarco, the Hamilton County coroner in Cincinnati, publicly warned users during a recent news conference: "Narcan may not save you on this one."