Early appearance of osteonecrosis of the jaw after zoledronic acid in a patient with a long history of taking oral bisphosphonates.

Osteonecrosis of the jaw (ONJ) is a serious side effect in patients receiving intravenous nitrogen-containing bisphosphonates (B). It has also been reported to occur due to oral administration of B. Most cases will appear after receiving B for more than 1 year. The authors report a case of a 67-year-old woman with osteoporosis who had received oral alendronate sodium for 2 years and stopped the treatment due to dyspepsia. 18 months later she was diagnosed with breast cancer and bone metastases. She started a treatment based on aromatase inhibitors and zoledronic acid (Z). She developed ONJ soon after the third administration. She was treated with antibiotics, anti-inflammatories and a chlorexidine colutory. She recovered 3 months later. ONJ secondary to Z may occur also earlier than it was thought in patients with a history of taking oral B.