Continuous Dentoalveolar Neuropathic Pain Response to Repeated Intravenous Ketamine Infusions: A Case Report

This article describes a case of continuous dentoalveolar neuropathic pain in which relief was obtained following repeated administration of intravenous infusions of a subanesthetic dose of ketamine. A 50-year-old female presented in 2006 with a 1-year history of constant sharp pain in the gingiva surrounding the maxillary left second premolar and second molar rated as 10/10 on a pain intensity scale. After multiple systemic medications failed to adequately manage the patient's pain, partial pain reduction was obtained (4/10) with daily use of methadone 50 mg in combination with application of a topical compound including lidocaine, amitriptyline, and carbamazepine to the affected area as needed. In July 2012, for reasons unrelated to the neuropathic pain condition, the patient underwent extraction of the maxillary right second premolar under intravenous sedation. Initially, a subanesthetic dose of ketamine was added to the sedation regimen for postoperative pain management; however, due to subsequent improvement of the dentoalveolar neuropathic pain, repeated intravenous infusions were recommended for further pain management. The patient's neuropathic pain condition was successfully managed by a total of five intravenous ketamine infusions repeated over a 4-year period of time. The patient's daily use of methadone was progressively reduced and finally discontinued. This case suggests a possible role for intravenous infusions of subanesthetic doses of ketamine as an adjuvant management option in patients suffering from intractable dentoalveolar continuous neuropathic pain conditions. Keywords: continuous neuropathic pain, ketamine, NMDA receptor, opioid tolerance, orofacial pain