Tramadol
"I have a bleeding disorder so can't take NSAIDs. Unfortunately, I also have arthritis and shoulder pain. I was taking Tylenol #3 but didn't like the mental clouding side effect. Tramadol has worked great for me. I take 100 to 300 mg a day, tending toward the 100 side with 300 being for active weekends of running and biking (300 spread out in 3 doses, not all at once, obviously). This works really well. I'm giving it an 8 because of the side effects (constipation and dry mouth). 

I've skipped a couple days with no problem and no overwhelming desire to take it (other than I hurt!)"