Safety and efficacy of prolonged outpatient ketamine infusions for neuropathic pain.

Ketamine has demonstrated usefulness as an analgesic to treat nonresponsive neuropathic pain; however, it is not widely administered to outpatients due to fear of such side effects as hallucinations and other cognitive disturbances. This retrospective chart review is the first research to study the safety and efficacy of prolonged low-dose, continuous intravenous (IV) or subcutaneous ketamine infusions in noncancer outpatients. Thirteen outpatients with neuropathic pain were administered low-dose IV or subcutaneous ketamine infusions for up to 8 weeks under close supervision by home health care personnel. Using the 10-point verbal analog score (VAS), 11 of 13 patients (85%) reported a decrease in pain from the start of infusion treatment to the end. Side effects were minimal and not severe enough to deter treatment. Prolonged analgesic doses of ketamine infusions were safe for the small sample studied. The results demonstrate that ketamine may provide a reasonable alternative treatment for nonresponsive neuropathic pain in ambulatory outpatients.