Ketamine combined with morphine for the management of cancer pain in a patient with meperidine tolerance and addiction.

Pain treatment of patients with opioid addiction and tolerance may be challenging due to their unexpectedly higher pain sensitivities and opioid requirements. It has been reported that the N-methyl-D-aspartate receptor is involved in mechanisms of tolerance to opioid analgesics. Recently enhancement of morphine induced analgesia by low dose ketamine addition to the treatment regimen has been reported. We report a cancer patient with meperidine tolerance and psychological dependency to the agent who was afterwards successfully treated with morphine-ketamine combination.