A doctor may prescribe four Dulcolax tablets to prepare a patient for a colonoscopy, notes the Atlantic Medical Group. It helps to clean out the intestines before a patient undergoes a bowel examination or surgery. Dulcolax works by boosting the movement of the intestines to allow the stool to come out.
Also known as a stimulant laxative, Dulcolax is a medication for constipation, explains WebMD. A patient takes this drug a day before undergoing a colonoscopy, as directed by a doctor. There may be other medications, such as Miralax, that a doctor prescribes. In addition, a patient should drink plenty of clear fluids on the day before the test.