Since your son has struggled for 10 months, 10 days of Muout Plus (Polyethylene Glycol) may not be enough, or the dose may need adjustment. Chronic pediatric constipation often requires a higher initial dose to clear accumulated stool (disimpaction) before maintenance. Please consult his paediatrician before changing medications; they may need to adjust the Muout Plus dosage or consider alternatives like lactulose. In the meantime, ensure he stays well-hydrated, gradually increases dietary fibre, and practices regular toilet sitting after meals. Seek immediate medical attention if he develops severe abdominal pain, vomiting, or blood in his stool.