Suprep usually starts working within a few hours, but the exact timing varies from person to person. Most people should plan to stay near a bathroom once they take it.
Typical onset
For many adults, bowel movements begin about 1 to 3 hours after the first dose of Suprep, although it can be as quick as 30 minutes or as long as about 4 hours in some cases. The second dose often works faster because the bowel is already partially emptied, sometimes starting within 30 minutes to 2 hours.
How long effects last
Once it starts working, expect frequent, often urgent watery bowel movements for several hours until the stool runs clear or pale yellow. It is common to be up for much of the evening or early morning depending on your dosing schedule, so staying hydrated and close to a toilet is important.
When to call your doctor
If there is no bowel movement at all within about 4 hours after taking Suprep, or if you have severe vomiting, dizziness, or signs of dehydration (such as very dry mouth, feeling faint, or not urinating), contact the prescribing doctor or on-call service for instructions. Always follow the timing and dietary instructions provided by the gastroenterology team, as they may adjust them based on your health conditions and procedure time.
