Efficacy of pamidronate in complex regional pain syndrome type I

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy (RSD), is a painful, disabling disorder for which treatment is difficult. The aim of this study was to determine the efficacy of pamidronate in a double-blind randomized placebo-controlled trial.

Patients referred to our regional multidisciplinary pain management center who fulfilled the International Association for the Study of Pain criteria for CRPS Type I were enrolled in the study over a 2-year period. Patients were administered, intravenously, either pamidronate, 60 mg as a single dose, or normal saline. Patients' pain scores, global assessment of disease severity scores, and functional assessment (SF-36) scores were documented at baseline and at 1 and 3 months.

Twenty-seven patients (18 female, 9 male; average age 45 years) were recruited, of whom 14 received pamidronate and 13 received placebo. Overall improvements in pain score, patient's global assessment of disease severity score, and physical function (SF-36) score were noted in the pamidronate group at 3 months, and improvements in role physical (SF-36) score were noted at 1 and 3 months. There was variability in pamidronate response among individuals.

Pamidronate may be a useful treatment option in the management of patients with CRPS Type I. Although treatment response was variable, the majority of patients improved. Early administration in tandem with other treatment measures is recommended.