Study to Evaluate the Efficacy of Lithium Carbonate in Spinal Cord Injury Patients With Neuropathic Pain

Inclusion Criteria: * Age 18 - 65; * Diagnosis of traumatic spinal cord injury; * Clinically diagnosed neuropathic pain; * Pain severity is at least 4 on a 11-point numeric rating scale at screening; * Pain present regularly for at least 6 weeks before enrollment; * Able to understand instructions and provide reliable pain assessments; * Subjects who are voluntarily signed and dated an Ethics Committee approved informed consent form; Exclusion Criteria: * Significant renal, cardiovascular, hepatic, infectious or psychiatric disease; * Significant brain injury with neurological deficits; * Debilitation or dehydration; * Addison's disease; * Recent (within 1 week) or current use of anti-diuretics or other drugs that interacts with lithium, such as tricyclic antidepressants, nonsteroidal antiinflammatory drug and tetracyclines; * A history of substance or alcohol abuse within past 1 year; * A need for elective surgery involving preoperative or postoperative analgesics or anesthetics during the study period; * Current pregnant or breast feeding, or female who has childbearing potential but is not willing to use an approved method of birth control; * Participation in any drug study in the last three months; * History of oral lithium intake for any reason; or * any criteria, which in the opinion of the investigator, suggests that the subject would not be compliant with the study protocol.