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

Abstract

Background There are no prospective, multicenter double-blind placebo-controlled randomized pharmacological trials for the treatment of pain predominant functional GI disorders in children. Aim Evaluate the efficacy of amitriptyline in children with pain predominant functional GI disorders. Methods 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 <35 kg; 20 mg/d >35 kg). Assessment of GI symptoms, psychological traits and daily activities before and after intervention. Pain was assessed daily with self-report diaries. Primary outcome: overall response to treatment (child's assessment of pain relief and sense of improvement). Secondary outcomes: effect on psychosocial traits and daily functioning. Results 90 children enrolled, 83 completed the study (placebo: 40, 30 females; drug: 43, 35 females). Patients reported feeling better 63%, worse 5% in amitriptyline arm vs. better 57.5%, worse 2.5% in placebo arm (p=0.63). Pain relief was excellent (7%), good (38%) in children on placebo and excellent (15%), good (35%) in amitriptyline (p=0.85). Logistic regression analysis of those reporting excellent or good response vs. fair, poor or failed showed no difference between amitriptyline and placebo (p=0.83). Children who had more severe pain at baseline in both groups (p=0.0065) had worse outcome. Amitriptyline reduced anxiety scores (p<0.0001). 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.