I'm not sure.

I want to say they gave me two stages of anesthetic, but I also think fentanyl was the first of the two stages (counter to what you're saying should have happened). But also, I'm at best an amateur at chemistry; even less when it comes to medicine. That said, reasonably certain what they gave me was not milky nor did it burn going in (you'll have to excuse me if I misremember any deets, it was my first time going under and I was irrationally nervous about it)

I could have some things mixed up, but it did stand out in my mind that they used fentanyl (and I remember how fuckin' nice it felt when they threw it in my veins). But that's how I remember it.