Thank you all for the input - it seems that Methadone is not the scary option we perhaps thought. He's on Fentanyl now, so how much worse can it be. It's primary the constant, high level pain he cannot cope with, as opposed to the weird sensations.

He's never really had any over the top side affects with any of the other drugs he tried, so I think he does have a high tolerance.

The last few days have been an improvement, so we have our fingers and toes crossed.

Linda