Polyethylene glycol 4000 without electrolytes versus milk of magnesia for the treatment of functional constipation in infants and young children: a randomized controlled trial

Background. Functional constipation is a common pediatric problem. Polyethylene glycol and milk of magnesia are osmotic agents used to treat constipation. There were few studies comparing the two laxatives for the treatment of functional constipation in infants and young children. Objective: To compare two laxatives, polyethylene glycol 4000 without electrolytes (PEG) and milk of magnesia (MOM), by evaluating the effectiveness, adverse effects, and patient compliance. Materials and methods: A randomized controlled trial was performed in 94 patients aged one-four years who attended at the pediatric outpatient clinic of Bhumibol Adulyadej Hospital and met the Rome III criteria for functional constipation receiving either PEG or MOM for four weeks. The primary outcome evaluation was the improvement rate. The secondary outcomes included the improvement of stool frequency, adverse effects, and compliance rate. Results: Eighty-nine patients completed the study, including 46 in the PEG group and 43 in the MOM group. Baseline characteristics of age, body weight, sex, initial stool frequency, and duration of constipation were similar between groups. At the four week follow-up visit, 91% of PEG-treated patients and 65% of the MOM-treated patients exhibited improvement (p=0.003). Patients in the PEG group had greater increase of stool frequency after treatment than patients in the MOM group. Overall, adverse effects were mild, transient and not different among groups, but there was more diarrhoea in MOM treated patients. No serious adverse effects were observed. Compliance rates were 89% for PEG and 72% for MOM (p = 0.041). Conclusion: PEG was more effective and had greater patient compliance than MOM for the management of functional constipation in infants and children aged one-four years.