Ketamine and Chronic Pain (Anesth Analg 2019;129:241–54)

IV ketamine infusions can be effectively used on a case-by-case basis, as a primary analgesic in patients with chronic pain refractory to more conventional treatments. The actual effect of IV ketamine among chronic pain patients may vary widely. IV ketamine is associated with improvement in pain scores observed during the infusion and lasting for ≥2 weeks and more. Reduction in pain is variable within a range of dosages, stronger analgesic effects were observed with higher dosages. Further research will focus on identifying the optimal dosing regimen, combination therapy with ketamine, the psychological effects, and long term effects.