Public health and law enforcement officials across the country are warning about a synthetic opioid that is up to 10 times more powerful than fentanyl.
Cyclorphine has increasingly appeared in the drug supply in the U.S., Canada, the United Kingdom and Europe since last year. Experts attribute this to China's new controls on a different class of synthetic opiates.
Cychlorphine has appeared in at least 10 states, according to data from the U.S. Drug Enforcement Agency released by the White House. In Tennessee, which has been hit particularly hard, cychlorphine has been involved in at least 40 deaths in and around Knox County alone since July of 2025.
One of the reasons health officials are urging caution: Cychlorphine will not appear on widely available fentanyl test strips, and it also isn't picked up by routine hospital opioid urine screens.
PBS News’ Tim McPhillips takes a closer look at what you need to know.