Yes, it was Nubain. Rutten and Kerr have name checked Nubain, Percs, and Vicodin, but Nubain was the one that they always kept handy.
If I had it on hand I'd be tempted to use Nubain, especially if I had acute pancreatitis. I.M. or S.C., not I.V.

I remember reading on pubmed decades back how out of many thousands of user cases in hospitals only a tiny handful had any problem with Nubain dependency. But it's different if you use it by yourself without a script or real need.
ESFitness had a problem with Nubain decades ago. Duchaine had a Nubain taper idea using tramadol which he thought wasn't addictive at all, problem is that is not true. As I recall ESFitness tried the tramadol detox.