Comparison of Two Methods for Bowel Preparation in Patients With Constipation

All patients were given oral instruction for bowel preparation on the day of appointment and re-instruction through phone call on two days before scheduled colonoscopy. They were instructed to have a regular lunch and take only clear liquid or low-residual food for the dinner on the day before colonoscopy. The participants began to drink the first 2 L of PEG at 7:00-9 PM on the day before colonoscopy at a rate of 250 mL every 15 minutes. On the day of the procedure, patients took the remaining 2 L 4-6 hours before colonoscopy.

The same as mentioned above. The participants began to drink the first 1.5 L of PEG at 2:00 PM and the second 1.5L of PEG at 8:00PM on the day before colonoscopy at a rate of 250 mL every 15 minutes. On the day of the procedure, patients take the remaining 1.0 L 4-6 hours before colonoscopy.