Methadone VS Hydromorphone - or both??

[IntenseNV]

I have used hydromorphone for 5 years and take between 30 and 35 mg per day, some days only 22 mg and some days as high as 45 mg. It all depends on the pain level. As someone in his 60s with acute and chronic degenerative disc disease, i have constant pain. Without medication, it would be difficult to do daily chores or anything other than lying down. I have a new pain doctor after all these years, and he wants me to try 15mg of methadone and well as 16mg of hydromorphone each day. I have never heard of someone taking a combination of the drugs, in my experience it has always been one or the other. I do know that the hydro is short acting/short shelf life and the methadone has a longer shelf life in the body. Has anyone taken both drugs at the same time? How will this affect any decision to get off both drugs in terms of withdrawal ( which i have done a couple times with the hydromorphone and was able to stay off as long as 6 months). thank you