Dr. Chris Jones speaking: Fentanyl is a class of drugs which includes fentanyl itself and then other fentanyl analogues and so far in the US we've seen between somewhere between 15 and 30 different analogues show up in the illicit drug supply.
That started in about 2013 where acetyl fentanyl showed up in Rhode Island and in the Northeast, we've subsequently seen the very high potent illicit fentanyl product Carfentanil showing up in many jurisdictions.
Other analogues like Furanylfentanyl a variety of different analogues are showing up and they're all different - they all work in the same way, but they have different potencies.
Some are more potent then fentanyl some are less potent then fentanyl.
And I think it's really this emergence of such a variety of synthetic opioids that is also leading to the rise in overdose deaths because the drug supply is unpredictable and individuals who are using drugs don't particularly know exactly what they are using.