Efficacy of amitriptyline in pediatric functional abdominal pain disorders: A randomized placebo-controlled trial.

Abstract

Amitriptyline improves symptoms in functional abdominal pain disorders (FAPD) in adults with variable results in pediatric studies. The study aims to evaluate the efficacy of amitriptyline in pediatric FAPD. In this open-label trial, children (≤18years) diagnosed as FAPD based on ROME IV criteria were randomized to amitriptyline or placebo for 12weeks. Post-treatment improvement of pain and quality of life (QOL) from the baseline were compared between the two groups. The mean age of 149 children (amitriptyline 75, placebo 74) was 11.3±3.5years (79 boys). There was a significant difference in pain improvement in terms of reduction in scores for intensity (3.4 vs 0.9), frequency (3.6 vs 0.6), duration (3.5 vs 0.9), and QOL (2.3 vs 0.9) between amitriptyline and placebo group (P<0.001 in all). Responders (>50% reduction) in pain was seen in 76% in amitriptyline compared with 14.9% in the placebo group (P<0.001). On multivariate analysis, the use of amitriptyline was the only factor predictive of response (odds ratio 24.1, 95% confidence interval: 9.1-64.6, P<0.001). Minor adverse events were comparable between the groups (25.3% vs 13.5%, respectively, P=0.07). Eighty-nine percent of children (24/27) who had extended treatment duration (6.8±1.8months) had pain improvement. After discontinuation of amitriptyline, 70% had sustained response over a mean follow up of 15.84±5.6months. A 3-month trial of amitriptyline gives sustained relief of pain in two-thirds of children with FAPD. The safety profile of the drug and its efficacy necessitate more frequent use in the clinical settings.