Reduction in constipation and laxative requirements following opioid rotation to methadone: a report of four cases.

Constipation is a common symptom in cancer patients, especially in those who are receiving opioid analgesics for pain. Although several articles have recently examined constipation with respect to causation and treatment, little research has been done to elucidate the effects of different opioids on the bowel. Recent research has found that laxative doses may be lower in patients using methadone as an analgesic, but changes in constipation were not measured. We report here on four cases in which patients had improvement in constipation and decreased laxative requirements following opioid rotation to methadone.