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Hello, I'm Dana Taylor, and this is a special episode of USA Today's The Excerpt.

Thank you. and this is a special episode of USA Today's The Excerpt. Picture this, a powerful synthetic opioid that quietly morphs into one of the nation's most lethal drug crises.

A drug thing can be slipped undetected into heroin, counterfeit pills of the nation's most lethal drug crises, a drug that can be slipped to undetected

and to heroin, counterfeit pills, the nation's bloodstream. You've seen and may have even been

touched by the devastating impact of fentanyl, and now a different class of ultrapotent synthetic

opioids called Nidazines are following an eerily familiar path. Just how dangerous are these

drugs and where are they coming from? Here to unpack those questions and more is Dr. Greg

McDonald, the chair of the Department of Forensic Medicine and Pathology at the Philadelphia

College of Osteopathic Medicine. Thanks for joining me on the excerpt, Dr. McDonald.

Thanks for having me.

First, these aren't new synthetics.

What's the origin story of netizens?

And have they ever been approved for human use?

They go back to 1950s when they were developed.

I believe it was in Switzerland, in a laboratory.

But because of the marked potency, the strength of these drugs, they were never approved

for medical uses. I don't believe in any country that I'm aware of.

I mentioned that these are ultra-potent synthetic opioids.

Are netizens even more potent than fentanyl? Can you compare the two for us? Yes, they are more

potent than fentanyl. Now, remember, the netizens, they're a group of opioids. So they're different,

...