Does Laxopeg Help To Treat Child Suffering From Constipation?

My daughter is 7yrs old and she is having constipation. Iam taking treatment with Dr.Sripathi paediatric urologist in chennai. He has given Looz for 3 months . And i also made my kid to go to toilet before school. When i went for checkup NOW its found in X-ray she still withholding bowel . Bit she is sitting in the bathroom for 20 min. How come she can t empty her stomach. Now he prescribed LAxopeg for 3 months. Will this be rectified. when is the exact time to give Laxopeg 1/2hr after dinner or before going to bed.