RESUMEN
BACKGROUND/AIMS: This study was designed to compare the efficacy and patient tolerance between standard bowel preparation using 4 liters of polyethylene glycol (PEG) solution and 4 liters of PEG preceded by the osmotic laxative, magnesium hydroxide in constipation and non-constipation group. METHODS: 173 outpatient colonoscopy, except for three patients who were not taking magnesium, were divided into constipation and non-constipation group. Then, the patients were randomly assigned to receive 4-liter of PEG solution or 4-liter of PEG plus magnesium hydroxide. The quality of bowel preparation was assessed using Ottawa scale, and satisfaction score was assessed using questionnaires. Solid stool, cecal intubation time, compliance, and side effects were assessed. RESULTS: Non-constipation group showed no significant differences between two groups. In constipation group, 4-liter PEG solution plus magnesium hydroxide induced the more effective colonic preparation (Ottawa scale 2.47+/-0.99 vs. 5.92+/-2.39, p<0.05), and less solid stool (0.67+/-0.72 vs. 1.38+/-0.65, p<0.05) compared with 4-liter PEG solution. CONCLUSIONS: Bowel preparation with magnesium hydroxide and 4 liters of PEG solution might reduce solid stool in constipation group, but could not improve preparation quality.