Zoledronic acid in pediatric metabolic bone disorders

Bisphosphonates (BPs) have been used widely since the 1990s and are considered a cornerstone for the treatment of osteoporosis (1). This class of drug has also been used to treat a variety of bone disorders other than osteoporosis in adults, such as Paget’s disease of bone, multiple myeloma, hypercalcemia and bone metastasis (2). Since the landmark report of its successful use in 1998 in a large series of children with osteogenesis imperfecta (OI), BPs have been increasingly used in children suffering from primary and secondary osteoporosis, as well as various skeletal disorders. Pamidronate, a second generation BP is the most widely used intravenous BP. It is given as a 4-hour intravenous infusion for 3 consecutive days in cycles every 2–4 months for an annual dose of 9 mg/kg. It has several beneficial effects in children with OI: increased bone mineral density (BMD), reduced fracture rate, and substantial improvement in functional status. More recently, several studies have demonstrated that zoledronic acid (ZA), a more potent third generation BP, can be used safely and effectively in childhood osteoporosis. ZA treatment offers greater ease and convenience of use, as compared to pamidronate, as it is administered as a single intravenous infusion over a shorter duration of 30 minutes, with a longer interval between infusions. This dosing schedule greatly reduces the need for repeated venous cannulation, and is more cost effective in terms of health care utilization. This makes ZA an attractive and efficient treatment option. This article describes the pharmacologic properties of ZA and summarizes safety and efficacy findings from clinical studies of its use in children with various skeletal disorders