A randomized controlled trial of amitriptyline versus gabapentin for complex regional pain syndrome type I and neuropathic pain in children

Background: Treatment of neuropathic pain in children is challenging, and requires a multimodal approach of pharmacologic, physical, and psychological therapies; however there is little evidence to guide practice. Amitriptyline and gabapentin are first-line drugs for treating neuropathic pain in adults, yet no studies have examined their efficacy, or compared them directly, to determine which might be better for pain relief and sleep disturbance in children.

Methods: After informed consent was obtained, 34 patients aged 7-18 years diagnosed with complex regional pain syndrome type I (CRPS I) or a neuropathic pain condition were randomly allocated to receive either amitriptyline or gabapentin. Patients were followed for 6 weeks and assessed for pain intensity, sleep quality and adverse events. We blinded study personnel, including health-care providers, participants, parents, the research coordinator and the data analyst. Patients then completed quantitative sensory testing (QST) and a psychosocial pain assessment with the team psychologist, within 1-3 days of the start of the trial.

Results: At the end of the 6-week trial, patients on both drugs had important reductions in pain, having surpassed the minimally important difference (MID) of 1. The difference between the groups however was not statistically significant. For the secondary outcomes, we found no statistically significant difference between the two drugs in sleep score or adverse events suggesting that both drugs improve sleep score to a similar degree and are equally safe.

Conclusions: Amitriptyline and gabapentin significantly decreased pain intensity scores and improved sleep. There were no significant differences between the two drugs in their effects on pain reduction or sleep disability.

Implications: Although larger, multi-centred trials are needed to confirm our findings, including long-term follow-up, both drugs appear to be safe and effective in treating paediatric patients in the first-line treatment of CRPS I and neuropathic pain over 6-weeks.