The use of rapid onset fentanyl in children and young people for breakthrough cancer pain

Background and aims: No published studies have looked at the dosing and use of rapid onset fentanyl preparations in children. The primary aim of this study was to assess whether there is a correlation between effective dose of rapid onset fentanyl and background oral morphine equivalent analgesia in children less than 18 years old. Secondary objectives included establishing whether there is a correlation between effective dose of rapid onset fentanyl and age and weight. Reported side effects were also reviewed.

Methods: This study is a retrospective case note review of all children less than 18 years old who received rapid onset fentanyl products in a tertiary paediatric oncology centre in England between 2010 and 2015. Correlations were analysed using Spearman's correlation coefficient as data was non-parametric.

Results: Data on 26 children (5-17 yrs; 13-100kg) was analysed. The most common diagnosis in children being given rapid onset fentanyl products was a solid tumour (84.6%). Eleven children used sublingual tablets, 17 used lozenges and one used a fentanyl nasal spray (three patients used two different preparations). The only significant correlation found was between dose of fentanyl lozenge and weight (r_s=0.81, p<0.001). Very few side effects were reported with the most frequent being nausea (8%) and sleepiness (8%).

Conclusions: Fentanyl lozenges seem to be safe and well tolerated in children as young as five years old, weighing as little as 13kg. Results suggest that children should always be started on the lowest available dose of chosen preparation and that this dose should be titrated according to response. This study demonstrates that there is no correlation between background opioid dose and effective dose of rapid onset fentanyl in children. This mirrors findings of similar studies in adults. There was a strong correlation between effective dose of fentanyl lozenge and weight. This may be in part due to clinicians being more inclined to increase fentanyl lozenge doses as the child is in control of when they have had enough medication. In contrast, buccal tablets are absorbed quickly and the child always receives the full dose, making clinicians more reluctant to titrate the dose.

Implications: This article presents initial evidence for feasibility and tolerability of fentanyl lozenges in children as young as five years old, who are on relatively low doses of background opioids. This could be of interest to clinicians who are looking for alternatives to oral opioids to manage breakthrough pain in children with cancer.