Interview with Silvano Adami, Professor in Rheumatology, Verona University.
Complex regional pain syndrome type I (CRPS-I), formerly known as RSD (Algodystrophy), is a severely disabling pain syndrome for which no definite treatment has been established. The pain is characterized as constant, extremely intense, and out of proportion to the original injury. The pain is typically accompanied by swelling, skin changes, extreme sensitivity, and can often be debilitating. It usually affects one or more of the four limbs but can occur in any part of the body and in over 70% of the victims it spreads to additional areas.
CRPS is ranked as the most painful form of chronic pain that exists today by the McGill Pain Index.
What is Neridronate?
Neridronate is an aminobisphosphonate (bisphosphonate), licensed in Italy for the treatment of osteogenesis imperfecta (OI) and Paget’s disease of bone (PDB). A characteristic property of neridronate is that it can be administered both intravenously and intramuscularly, providing a useful system for administration in homecare. In this review, we discuss the latest clinical results of neridronate administration in OI and PDB, as well as in osteoporosis and other conditions. We will focus in particular on the latest evidence of the effect of neridronate on treatment of complex regional pain syndrome type I. To this day Neridronate is not available in the US as it is under trial by the FDA and may take up to 10 years before it is finally approved in the United States. The earlier the diagnosis and the sooner the neridronate treatment is administered, the higher are your chances of eliminating the pain and disability CRPS/RSD.
Treatment of complex regional pain syndrome type I with neridronate: a randomized, double-blind, placebo-controlled study by Varenna M1 ,Adami S ,Rossini M ,Gatti D ,Idolazzi L , Zucchi F, Malavolta N, Sinigaglia L .
Eighty-two patients with CRP-I at either hand or foot were randomly assigned to i.v. infusion of 100 mg neridronate given four times over 10 days or placebo. After 50 days the former placebo patients were given open label the same regimen of neridronate.
Within the first 20 days, visual analogue scale (VAS) score decreased significantly more in the neridronate group. In the following 20 days, VAS remained unchanged in the placebo group and further decreased in the active group by 46.5 mm (95% CI -52.5, -40.5) vs 22.6 mm (95% CI -28.8, -16.3) for placebo group (P less than 0.0001). Significant improvements vs placebo were observed also for a number of other indices of pain and quality of life. During the open-extension phase in the formerly placebo group the results of treatment were superimposable on those seen during the blind phase in the active group. A year later none of the patients was referring symptoms linked to CRPS-I.
In patients with acute CRPS-I, four i.v. infusions of neridronate 100 mg are associated with clinically relevant and persistent benefits. These results provide conclusive evidence that the use of bisphosphonates, at appropriate doses, is the treatment of choice for CRPS-I.