Protocoles instaurations have been created to use methadone for switching. Pain experts have developed there own protocol.
There is now plenty of protocols to convert to methadone but no systematic comparative study. New methadone classification has been published (SAD mode):
1. How to Switch : rapidly or progressivly
2. Administration mode: fixed dose and rescue dose or ad libitum
3. Dose calculation mode: progressive ratio (depending of morphine equivalent daily dose [MEDD]) or fixed ratio, for daily dose or unitary dose.