01.2023
Author Prof. E. Harms, University Department of Pediatrics Münster

The placebo effect is the measurable efficacy of a placebo. Significant placebo effects have been documented primarily in the fields of pain management and the treatment of functional gastrointestinal disorders. In the past, it was thought that blinding of patients was the prerequisite for measuring a placebo effect. In recent years, however, studies with adults have shown that the efficacy of placebos could also be determined if the subjects knew that they were given one (OLP, open-label placebo). In a multicentre, randomized, crossover clinical trial, a US group investigated whether an OLP administration in children with functional abdominal pain or irritable bowel syndrome can reduce the patients’ complaints [1].

Thirty patients aged between 8 and 18 years – 16 with functional abdominal pain, 14 with irritable bowel syndrome – were enrolled in the study.
The patients and their families were told that the placebo did not contain any active ingredient, but that the medication has shown to be effective in the past. The patients kept a pain diary.

They were allowed to take hyoscyamine 0.125 mg tablets as a rescue medication up to 4 times a day during the study if necessary. The placebo – 1.5 ml of orally administered sucrose solution – was given twice a day. 2 groups were formed. 

Group 1: 3-week diary and rescue medication if needed, followed by 3 weeks of placebo administration, diary and rescue medication if needed.

Group 2: reverse order. During the OLP period, the number of pain episodes (from 45.0 to 39.9) and the consumption of rescue medication (from 3.8 to 2.0) decreased significantly in both groups.