Methadone in treatment of tenesmus not responding to morphine escalation.

Tenesmus is a painful sensation of incomplete evacuation of the bowel and is often associated with poorly localized perineal pain. We describe a 68-year-old man with locally advanced rectal carcinoma metastatic to lung and with unbearable rectal-perineal pain unresponsive to morphine and ketorolac. Treatment with oral methadone was successful and pain improved considerably. Methadone has been reported to improve pain relief in patients with morphine resistance, and it is lipophilic and exerts a lesser activity on opioid receptors in the gastrointestinal tract.