Pharmacological interventions have not been successful in the treatment of pediatric FAP hitherto. Neuromodulators are suggested to be efficacious based on the disease pathophysiology and evidences from studies on adults.

This randomized clinical trial was conducted on 117 FAP patients aged 6-18 years. We randomly assigned patients to receive buspirone or placebo for 4 weeks, with the adjusted dosage for age. Participants completed the questionnaires assessing pain, depression, anxiety, somatization and sleep disturbances at baseline, at the end of the 4-week therapy (first follow-up), and 8 weeks after medication discontinuation (second follow-up). The primary outcome was treatment response rate, defined as reduced pain scores of ≥2 or reporting no pain at follow-up assessments.

Ninety-five patients completed the 4-week therapy (48 and 47 in buspirone and placebo groups, respectively). Both buspirone and placebo reduced pain after 4 weeks of treatment and these effects were persistent 8-weeks after medication discontinuation (p<0.001 for both groups at weeks 4 and 12). Treatment response rate for buspirone and placebo was 58.3 % and 59.6 % at week 4 (p=0.902), and 68.1 % and 71.1 % at week 12 (p=0.753), respectively.