pain
"Find the use of these to be easy to take, and has been very helpful to me.  I have had no side effects, other than the 12 hour ends a little bit less than this! 
Have found that taking them at 12 hour intervals has not been quite right. 
I see that sometimes I have a little less than 12 hour help, and other times have gone 14 to 15 hours and been fine. Depends on digestion maybe. Urinalysis showed the rate in my body to be less sometimes and not sure why?
Do know that while I was sick with the flu, I wasn't able to keep down these, and did have side effects of withdrawals."