An unusual case of chronic neuropathic pain responds to an optimum frequency of intravenous ketamine infusions

The effective treatment of patients suffering from a variety of difficult p ain syndromes, including phantom pain and other neuropathic pains, remains a clinical challenge. Neuropathic pain has been shown to respond to drugs t hat block the N-methyl-D-asparate (NMDA) receptor, such as ketamine and ama ntidine. A 44-year-old woman with a previous right-sided forequarter amputa tion presented to the Palliative Medicine Team complaining of neuropathic p ain in her left arm, which was neurologically intact. The pain was treated with repeated infusions of intravenous ketamine. Twenty-one infusions were given over a period of four months. The pain intensity experienced by the p atient lessened at the frequency of the ketamine infusions increased. This finding has not been described previously and supports the theory that ther e may be an optimum frequency of ketamine infusions to achieve adequate pai n control. (C) U.S. Cancer Pain Relief Committee, 2001.