Efficacy of Low Analgesic Doses of Ketamine Associated With Opioids in Refractory Cancer Pain Treatment

Long-term opioid therapy is commonly administered for the management of severe cancer pain. Increasing doses of opioids are titrated against effects until analgesia is achieved or intolerable adverse effects occur. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been reported to improve analgesia in patients with uncontrolled pain receiving high doses of opioids. This study aims at determining the effectiveness of ketamine as an adjuvant to opioids in relieving cancer pain.