Prescribing of zoledronic acid in a tertiary outpatient hospital setting.

Background: Zoledronic acid (ZA) is an intravenous bisphosphonate approved for the prevention and treatment of cancer skeletal-related events.

Objective: Our aim was to analyze the prescription patterns of ZA in the cancer outpatient clinic.

Method: We performed a retrospective chart review of all patients who received at least 1 dose of ZA from January 2009 until December 2010 in our institution. The patients' follow-up period was defined from the administration of the first dose until February 2011.

Results: The sample comprised 345 patients: 31.9 % had breast cancer, 14.5 % prostate cancer, 29.0 % multiple myeloma, and 24.6 % other solid tumors. A total of 4,546 doses were administered; 2,749 (60.5 %) without intravenous chemotherapy. 71.1 % of patients with breast cancer, 86 % with prostate cancer, 60 % with multiple myeloma and 44.6 % with other solid tumors, received ZA without intravenous chemotherapy throughout bisphosphonate treatment. Doses were adjusted in one-third of cases. Administration every 4-weeks was the most frequent schedule. Median duration of treatment varied between 15.0 months for breast cancer and 4.2 months for other solid tumors.

Conclusion: Most of ZA prescriptions in cancer outpatients followed the labeled indications. The percentage of ZA doses administered without intravenous chemotherapy was 60.5 %.