Complications of pamidronate therapy in paediatric osteoporosis

Abstract

Pamidronate, used for the treatment of paediatric osteoporosis, reduces the fracture rate and improves ambulatory status. Intravenous pamidronate therapy has known complications which have not been stratified based on its dose and distribution. This study aims to assess the early minor and major medical and late surgical complications and the effect of the dose and regimen of infusion on these events in paediatric osteoporosis. Retrospective cohort. Three regimens for pamidronate infusion were followed in sequential periods in 10years. Regimen A delivered 1.5mg/kg/day as a single dose once in 3months. Regimen B delivered 2mg/kg/day for 3days twice a year, while regimen C delivered 1mg/kg/day for 3days every 3-4months. Adverse events were classified as early (major and minor) or late (surgical). Forty-eight children received 158 infusions using one of the three regimens. Twenty-nine complications occurred in 24 children. A significant difference in the complication rate was present among the three regimens (P=0.005). Nineteen children had minor complications, mainly febrile reaction or asymptomatic hypocalcaemia. Four major complications consisting of one seizure, one respiratory distress and two hypocalcaemic tetany were encountered, all with regimen B. Intraoperative complication faced was loss of position due to splintering of the cortex while rush rodding. This was seen in 20% of the long bone segments operated in those who received pamidronate as compared to 4.4% of the segments which were operated prior to the initiation of pamidronate therapy; the odds of splintering were 5.4 times higher for those patients who were bone segment rodded after pamidronate therapy. Intravenous pamidronate is associated with complications in 50% of children with paediatric osteoporosis, with a dose-dependent significant difference. Major complications are not uncommon with higher doses and can be avoided by increasing the number of doses per year and decreasing the dose per cycle. Surgical difficulty, when possible, can be avoided by correcting any major deformities at presentation prior to the induction of pamidronate therapy.