A new synthetic opioid as powerful as fentanyl is causing overdose deaths at an ever-increasing rate, experts warn.
What’s worse, the designer drug is legal in most places in the United States.
Isotonitazene — commonly referred to as “iso” — is causing around 40 to 50 overdose deaths a month in the United States, compared with about six per month last summer, said Dr. Antonio De Filippo, an addiction specialist and medical director at Delphi Behavioral Health Group in Fort Lauderdale, Fla.
“The numbers are going up as it becomes more popular and widespread,” De Filippo explained.
Iso is a synthetic version of etonitazene, an opioid first reported in 1957 but not approved for medical use because it is highly addictive and very dangerous.
Iso appears to be slightly more potent than fentanyl, which itself is as much as 100 times more powerful than morphine, according an analysis of the new drug published last year in the journal Drug Testing and Analysis.
“The emergence of this novel synthetic opioid is a major public health concern,” said Dr. Robert Glatter, an emergency physician with Lenox Hill Hospital in New York City. “The fact that it has similar potency to fentanyl makes it ripe for abuse and misuse, leading to respiratory depression, along with increased risk for death.”
Etonitazene is a controlled substance in the United States, but iso remains legal at the national level because its chemical structure differs slightly, said Pat Aussem, director of clinical content and development at the Center on Addiction in New York City.
Ohio issued notice in May that it intends to place isotonitazene on the state’s list of Schedule I controlled substances.
“From a purchasing standpoint, a lot of it is being sold online legally by Chinese suppliers offering bulk deals,” Aussem said. “The U.S. challenged China to crack down on fentanyl. Chemists there are looking for other ways to fill the demand.”
China banned fentanyl and all of its derivatives in April 2019. Within months, Chinese chemists turned to iso and other members of its opioid family, a class of drugs called benzimidazoles.
Iso was first reported in August 2019 based on analysis of seized drugs in Europe and Canada, the Ohio Board of Pharmacy said.
Iso comes in a yellow or off-white powder that can be cut into other drugs, Aussem said. Iso has been detected in the blood of overdose victims in Illinois and Indiana, who took it mixed with cocaine.
The drug also is being pressed into counterfeit pills. Canadian police seized 1,900 pills in March that bore the markings of dilaudid, but proved to be iso in lab tests, Aussem said.
Aussem suspects that iso already is more widespread in the United States than current estimates.
“My suspicion is because it’s not on the on the radar of many people doing toxicology reports, the more it becomes on their radar we’ll see those numbers increase,” Aussem said of iso-related overdose deaths.
Iso is raising concern among experts for a couple of reasons.
First, iso might not trigger the test strips that drug users utilize to test for the presence of fentanyl in other illicit substances, since it’s not a widely used opioid, Aussem said.
“Users think they’re doing the safe thing by testing the substances they’re getting, but it may not show up,” Aussem said.
Second, police have indicated that iso will respond to the lifesaving overdose drug naloxone, but that someone might need several doses for it to be effective, Aussem continued.
“A single dose of naloxone may not do the job, so that’s another risk factor,” Aussem said.
Iso is the latest example of “whack-a-mole” efforts to combat the opioid epidemic, Aussem said, in which chemists come up with new and highly potent synthetic opioids to replace whatever drugs have been outlawed.
“It’s always going to be something else,” Aussem said. “We can keep trying to go after these different variants of opioids, but at the end of the day we just need a comprehensive strategy.”
Such a strategy would include public education and awareness campaigns, drug use screening and early intervention, overdose prevention through the widespread availability of naloxone, and expanded access to drug treatment and mental health programs, the Center on Addiction says.
The Ohio Board of Pharmacy has more about isotonitazene.
SOURCES: Antonio De Filippo, M.D., addiction specialist and medical director, Delphi Behavioral Health Group, Fort Lauderdale, Fla.; Robert Glatter, M.D., emergency physician, Lenox Hill Hospital, New York City; Pat Aussem, director, clinical content and development, Center on Addiction