There's been some isotonitazene showing up in Vancouver, BC lately. hasn't there? In those white triangular Dilaudid presses, IIRC.
I've heard it feels better than fent, so the junkie hedonist in me has a desire to try it but the rationalist citizen in me has a dread of anything stronger than fent. Putting both of those minds together, I've started to think more critically about fentanyl. I wonder if its "strength" that makes it so deadly, since it comes into the US diluted to 7-10% purity. That's still ~2.5x stronger than pure heroin, which is significant but not the impression you get on the news, and I think it's usually knocked down again before it's retailed.
The heavy dilution that's happening at the point of production also makes me wonder if "hotspots" have really been responsible for as a high proportion of ODs as I've been lead to believe. I don't know nearly enough about the miscibility of powders or the blending techniques used in Sinaloa to know with any certainty, but it intuitively seems better to have the dilution being done earlier in the process, before it's broken down into doses (bags) or even meta-doses (kilos).
One point of major importance which I never learned from mass media discussion was the fact that there are differences between opiates in the average time they take to cause death in overdose. Even if two ODs are caused by equivalent doses of fentanyl and heroin, the fent OD leaves you with a substantially shorter window of time to be resuscitated. Learning this actually convinced me more than anything else not to use fent by myself, even in very conservative doses and with a big heroin tolerance.