Opioid withdrawal during risperidone treatment

A small but significant percentage of opioid-dependent patients will requir e neuroleptic treatment. Several classes of drugs have been shown to affect opioid metabolism. Two patients who were hospitalized with a diagnosis of opioid dependence received concomitant treatment with opioids and risperido ne. After receiving risperidone for several days, both patients exhibited s ymptoms of opioid withdrawal despite having no change in their opioid doses . These withdrawal symptoms resolved soon after risperidone was discontinue d. This finding suggests the possibility that risperidone may precipitate o pioid withdrawal in opioid-dependent patients.