Choreoathetoid movements associated with rapid adjustment to methadone.

Choreatiform hyperkinesias are known to be occasional movement abnormalities during intoxications with cocaine but not opiates. This is a case report of euphoria and choreoathetoid movements both transiently induced by rapid adjustment to the selective mu-opioid receptor agonist methadone in an inpatient previously abusing heroine and cocaine. In addition, minor EEG abnormalities occurred. Possible underlying neurobiological phenomena are discussed.