Multicenter, Randomized, Placebo-Controlled Trial of Amitriptyline in Children With Functional Gastrointestinal Disorders

Background & Aims

There are no prospective, multicenter, double-blind, placebo-controlled, randomized pharmacologic trials for the treatment of pain-predominant functional gastrointestinal disorders in children. The aim of this study was to evaluate the efficacy of amitriptyline in children with pain-predominant functional gastrointestinal disorders.

Methods

In this multicenter placebo-controlled trial, children with irritable bowel syndrome, functional abdominal pain, or functional dyspepsia were randomized to 4 weeks of placebo or amitriptyline (10 mg/d, weight <35 kg; 20 mg/d, weight >35 kg). Assessment of gastrointestinal symptoms, psychological traits, and daily activities occurred before and after intervention. Pain was assessed daily with self-report diaries. The primary outcome was overall response to treatment (child's assessment of pain relief and sense of improvement). Secondary outcomes were effect on psychosocial traits and daily functioning.

Results

Ninety children were enrolled, and 83 completed the study (placebo, 40 children [30 girls]; drug, 43 children [35 girls]). A total of 63% of patients reported feeling better and 5% feeling worse in the amitriptyline arm compared with 57.5% feeling better and 2.5% feeling worse in the placebo arm (P = .63). Pain relief was excellent in 7% and good in 38% of children receiving placebo compared with excellent in 15% and good in 35% of children treated with amitriptyline (P = .85). Logistic regression analysis of those reporting excellent or good response versus fair, poor, or failed response showed no difference between amitriptyline and placebo (P = .83). Children who had more severe pain at baseline in both groups (P = .0065) had worse outcome. Amitriptyline reduced anxiety scores (P < .0001).

Conclusions

Both amitriptyline and placebo were associated with excellent therapeutic response. There was no significant difference between amitriptyline and placebo after 4 weeks of treatment. Patients with mild to moderate intensity of pain responded better to treatment.

Abbreviations used in this paper: CDI, Children's Depression Inventory, FGID, functional gastrointestinal disorders, IBS, irritable bowel syndrome, ITT, intention to treat, NNT, number needed to treat, STAIC, State-Trait Anxiety Inventory for Children, TCA, tricyclic antidepressant