This chapter covers both types (1 and 2) of complex regional pain syndrome (CRPS). CRPS type 2, also known as causalgia, is a true neuropathy. Of all of the types of neuropathic pain, CRPS (either type) is the most resistant to pharmacotherapy. Even traditionally endorsed approaches such as sympathetic blockade are found poorly efficacious in Cochrane review. In fact, RCT evidence does not conclusively confirm utility for any agent for CRPS. For CRPS type 2, two trials of IV infusion of bisphosphonates find that pain may be reduced by alendronate or clodronate. The anticonvulsant gabapentin, effective in a broad range of neuropathic pain syndromes, is of little utility in CRPS. There is limited evidence for use of systemic corticosteroids for CRPS type 2. This chapter finally discusses a small trial, assessing PO prednisone that has found some benefit compared with placebo.