Methadone has very high cardiac risks and it stays in your system longer than the meds you are used to taking.....
I'm so sorry your doctor won't help you with this!
I understand you wanting to avoid the misery of withdrawal.....I'm having to taper very slowly from the Fentanyl patch....(for Neuropathy pain).....

Maybe try using the 'search' feature at the top of the page and type in methadone to get more info on it. Other posts will pop up to give you more information. I'm not very well-versed in that particular med....just going by what I've heard from very knowledged folks here.
Also try seeking out other alternatives to avoiding withdrawal......Hopefully this forum will have some good input for you. Actually that would be a good new thread discussion to start....something like "How to avoid withdrawals"....and maybe others will chime in with some suggestions.
I'll keep an eye on your threads, cuz I may need to know more about this if I have a hard time getting off the lowest dose of the patch.....
Good Luck.
Rae