Nitazenes found in 5 overdose deaths in Philly – here’s what they are and why they’re so deadly

Nitazenes are a class of synthetic opioids that contains more than 20 unique compounds, including isotonitazene, which was first identified in 2019 and is known on the streets as ISO. It also includes protonitazene, metonitazene and etonitazene. Nitazenes are psychoactive substances, or “designer drugs,” that aren’t controlled by any laws or conventions but pose significant health risks to the public. These substances have recently surfaced as illegal street drugs.