A Study of Prucalopride For Functional Constipation in Children and Teenagers

Functional constipation is a condition when it is very hard to pass a stool that is not due to any other health problem or to medicines being taken. This condition is more common in children and teenagers. This study has 2 parts: The main aim of the 1st part of the study is to learn if a medicine called prucalopride can improve bowel movements in children and teenagers with functional constipation. Another aim is to check for side effects from 2 different doses of prucalopride. The main aim of the 2nd part of the study is to continue to check for side effects from 2 different doses of prucalopride. In the 1st part, at the first visit, the study doctor will check who can take part. Participants who take part will be picked for 1 of 3 treatments by chance. * A low dose of prucalopride once a day. * A higher dose of prucalopride once a day. * A placebo once a day. In this study, a placebo will look like prucalopride but will not have any medicine in it. Participants will be treated with prucalopride or a placebo for 12 weeks. Participants who took prucalopride will continue to the 2nd part of the study. They will have the same treatment as they did in the 1st part of the study. They will continue with their treatment for another 36 weeks. Participants who took placebo in the 1st part of the study will receive prucalopride in the 2nd part of the study. They will be picked for a low dose or a high dose of prucalopride by chance. Participants will visit the clinic a few times during treatment. The clinic staff will also telephone the participants, or their parents or caregivers throughout treatment for a check-up 4 weeks after last treatment, the clinic staff will telephone the participants, or their parents or caregivers for a final check-up.