As SoCall says, probably worth discussion with your AME.
I guess the bottom line is, would I be happy putting my family on a plane when the captain is taking tramadol or codeine ? Probably not.
By the same rule, would I be be happy putting my family on a plane when the captain has severe pain ? Probably not.
Are there any alternative adjuncts ?
http://www.nice.org.uk/nicemedia/liv...9554/39554.pdf
Keep us popsted, it's an interesting question.