Butorphanol
"I was given STADOL because I was at 3 cm for so long, yet my contractions were getting unbearable (can't get the epidural until 4 cm).  The nurse told me, it works for some people and not for others. I am assuming it either takes the pain away or it doesn't. Well, it literally made me INSTANTLY start sweating, and my eyes were rolling in the back of my head.  However, no pain relief.  I got extremely restless and an intense feeling of confusion and dysphoria.  I was so unprepared for that feeling, it's horrible.  Being in a hospital, in labor, confused, restless, still feeling everything.  I researched it when I got home and apparently, only somewhere around 1% experience this.  Just pray you're the lucky 99%."