Opioids are frequently used for the treatment of chronic pain, and patients taking high doses are at increased risk of complications and adverse opioid-related events. Ketamine is appealing as an opioid adjunct because of its lack of respiratory depression and potential prevention of hyperalgesia and central sensitization. We present a case in which a ketamine infusion was utilized over a 7-day period to provide rapid taper of a daily dose of 400 mg of morphine equivalents to less than one-third of that dose on discharge with unchanged pain levels and no symptoms of opioid withdrawal.