ACUTE PHASE REACTIONS AFTER ZOLEDRONIC ACID INFUSION: PROTECTIVE ROLE OF 25-HYDROXYVITAMIN D AND PREVIOUS ORAL BISPHOSPHONATE THERAPY

Objective: The most common adverse reaction to zoledronic acid (ZOL) infusion is the acute phase reaction (APR), characterized by transient, usually mild, flu-like symptoms. Previous treatment with oral amino-bisphosphonates (BPs) was reported as an independent protective factor for APR, and an association between APR and 25-hydroxyvitamin D (25(OH)D) levels in BP-naïve patients treated with ZOL was identified. The aims of our study were to confirm this association and to see if it was different in patients previously treated with oral BPs compared with BP-naïve patients and to investigate the role of 25(OH)D for the time of APR onset.