Sutab is a tablet-based bowel prep for colonoscopy that works as an osmotic laxative. Its active ingredients, sodium sulfate and magnesium sulfate, are salts your intestines can’t absorb well. When these salts sit in your gut unabsorbed, they pull large amounts of water into the bowel through osmosis, producing watery diarrhea that flushes out stool until your colon is clean enough for a doctor to examine it.
The Osmotic Process Behind Sutab
Your small intestine has a limited ability to absorb sulfate. Sutab exploits this limitation. When you swallow the tablets, the sulfate salts dissolve but largely stay inside your digestive tract rather than crossing into your bloodstream. Because there’s a high concentration of dissolved salts sitting in your intestines, water gets drawn in from surrounding tissues to balance things out. This flood of water loosens and liquefies everything in your colon, triggering repeated bowel movements that progressively clear the way for your colonoscopy.
This is the same basic principle behind older liquid bowel preps. The difference is the delivery format: tablets instead of drinking a large volume of salty or chemical-tasting liquid.
What You Actually Take
A complete Sutab prep involves 24 tablets, split into two doses of 12 tablets each. You swallow each tablet with sips of water, drinking a full 16 ounces over about 15 to 20 minutes. Then, roughly an hour after your last tablet, you drink another 16 ounces of water over 30 minutes. Thirty minutes after that, you drink a third 16-ounce container of water.
The timing of the second dose depends on when your colonoscopy is scheduled, but the pattern is the same: 12 more tablets with water, followed by two more rounds of 16 ounces each. On top of all this, you need at least 12 tall glasses (8 to 10 ounces each) of clear liquids throughout the day. The water isn’t optional. Because Sutab pulls so much fluid into your bowel, replacing that fluid is essential to avoid dehydration.
How Well It Cleans the Colon
In clinical trials, Sutab achieved successful bowel cleansing (rated “good” or “excellent” by the doctors performing the colonoscopy) in 92% of patients. That was comparable to the 89% success rate seen with a standard liquid prep containing polyethylene glycol, one of the most commonly prescribed alternatives. In other words, the tablet format doesn’t sacrifice effectiveness.
Patient experience was notably better with the tablets. In surveys, 78% of people who used Sutab said they’d request it again for a future colonoscopy, compared to 67% of those who used the liquid prep. Even patients who had done a liquid prep before and could compare the two reported a better overall experience with Sutab.
Common Side Effects
About half of patients in clinical trials reported at least one gastrointestinal side effect, which isn’t surprising for a product designed to empty your entire colon. The most common issues across two large studies were:
- Nausea: 48% to 52% of patients
- Abdominal bloating: 29% to 34%
- Vomiting: 16% to 23%
These numbers are roughly in line with what people experience on liquid preps as well. Nausea tends to be the biggest complaint. Taking the tablets slowly rather than rushing through all 12 at once, and keeping up with clear liquids, can help. The bloating typically comes from the large volume of water accumulating in your intestines before the bowel movements begin in earnest.
Who Should Be Cautious
Because Sutab works by flooding your intestines with water pulled from your body, it can cause significant shifts in hydration and electrolyte levels. People with kidney problems are at higher risk, since their bodies may struggle to handle the extra magnesium and sodium from the tablets. Those with severe gastrointestinal conditions that slow the movement of food through the digestive tract, like gastroparesis or bowel obstruction, may not be good candidates either, since the tablets need to move through the system to work properly.
Anyone with heart failure or who takes medications that affect kidney function or electrolyte balance should make sure their prescribing doctor knows before starting the prep. The fluid shifts involved are temporary but can be significant enough to matter for people with these conditions.