When switching from methadone to opiates does the long term use of the methadone curtail the effects of the opiates or does it take a certain period after stopping methadone use for the opiates to reach their peak performance?

when switching from methadone to opiates does the long term use of the methadone curtail the effects of the opiates or does it take a certain period of time after stopping methadone use for the opiates to reach their peak performance?

Trial and error. Rotation to another opioid from Methadone (ME) has been given little attention, an exception is Walker (2008) (http://www.ncbi.nlm.nih.gov/pubmed/18980450) that provides a proposed dosage ratio for the rotation.

Much will depend on your particular metabolism and history of ME use. There is a cross-tolerance between ME and other opioids. Certainly ME blocks the action of other opioids (by design) and there will be a transition period to peak effectiveness of the newly substituted opioid.

Hope that helps.