Introduction

Bisphosphonates are effective adjuvants in bone pain when the cause is bone destruction or disordered architecture.  Examples include metastatic malignant disease and osteogenesis imperfecta, but bisphosphonates are used in an increasingly wide range of other life-limiting conditions in which bone pain is a feature.

Dose

Each dose is given as two consecutive infusions of 0.5mg/kg disodium pamidronate, made up in 100mg normal saline (concentration not more than 0.2mg/ml) and infused over one hour.  There should be 24 hours between the two infusions.  The total dose is therefore 1mg/kg.

If the child is not receiving intravenous maintenance fluids, each infusion of pamidronate should be preceded by 60 minutes’ intravenous pre-hydration using normal saline given at 500% normal maintenance rate.

Investigations

An assessment of bone density should be made at baseline (prior to first treatment) and then on an annual basis for children receiving regular bisphosphonate therapy.

Serum calcium should be measured prior to and after receiving 1mg/kg (two infusions) of pamidronate.

Frequency

In adult palliative medicine, intravenous pamidronate is often given as a single infusion every three or four weeks while a benefit is noted.  In paediatric endocrinology it is infused in three daily fractions every three months.  The latter, more cautious approach is due to hypothetical concerns about potential effects on bone-remodelling during adolescence.

If thse concerns are not relevant (as is usual in palliative care), pamidronate should be given monthly while it is providing benefit.  Otherwise, it can be given three monthly for a year, followed by bone scans to re-assess impact on bone density.  This should be done in discussion with the palliative care and endocrinology teams.

Duration of treatment

The effectiveness of bisphosphonates in bone pain can be clear after only a few days, but additional benefit can appear for many months.  Judgement regarding its effectiveness  should be made after four doses and the drug discontinued if there is no benefit.