Yeah, before I started Sub, the pain doc offered to prescribe me Methadone. It was going to be a script, not something I had to go get everyday. My MIL is on Methadone for RA and she gets a script too. If you take Sub for pain, which I ended up doing, you do have to take it throughout the day and the more accurately you space your doses, the better. I found it wasn't fantastic for pain, but it helped to a point.
First you take a drink, then the drink takes a drink, then the drink takes you. ~F. Scott Fitzgerald