I ve been on Demerol for about 10 years for my chronic back pain & was able to remain mobs this is what I was taught as a good nurse. I was taking 4-5 50 mg.daily. Now they cut me down to 2 a day so needless to say I ve become less mobile because I hurt. I m allergic to Tylenoln so that cuts out lotss of meds. I have CHF so many others cause fluid retention. I tried for 5 years to find something that helped without side effects. that was Demerol provided the RX at painmanagement.