Laxative therapy in children with functional abdominal pain

INTERVENTION: Macrogol 4000, starting dosage 20 g/day, to increase every 2 days with 10 g in case of insufficient result until a maximum dosage of 50 g/day. The dosage should be adjusted guided by the stool consistency with the help of the (adjusted) Bristol Stool Form Scale. The intervention has a total duration of 4 weeks. CONDITION: Chronic abdominal pain, Functional abdominal pain, Children ; ; PRIMARY OUTCOME: Pain score (Wong‐Baker Faces Pain Score): % with score 0 (pain free) SECONDARY OUTCOME: Pain score: % decrease of pain in last week of intervention phase versus last week of run‐in phase. INCLUSION CRITERIA: 1. Age 4‐16 years 2. Fulfilling the Rome IV criteria for functional abdominal pain disorders, with exception of the criterion for IBS‐patients that the pain does not resolve with resolution of constipation