How does colonoscopy prep work?
Colonoscopies detect colon and rectal cancers while they are still small and treatable, but they also are used to find and remove polyps, which are small growths that can develop into cancer. To see these growths, the doctor needs a clear view during the procedure. This requires emptying the colon of its contents.
If the colon isn’t completely clean, the danger is we may miss tumors or polyps. It also could lead to a longer colonoscopy because we need to spend more time washing away waste to see more clearly.
The preparation process may differ slightly between medical centers and doctors, or from patient to patient. You doctor will explain exactly what you should do. In general, the process involves a liquid diet and laxatives.
The form of laxatives can vary. We generally prescribe four liters of a generic lavage solution, which is cheap and easy to get. Four liters is a lot to drink. It’s the equivalent of nearly seven 20-ounce bottles of soda. Some patients can get away with drinking half of that if they take Dulcolax tablets first.
Many patients ask us about alternatives to this part of the prep: “I heard from a friend you can just take a pill.” This is sort of true, but it’s not one pill, it’s 32. And it has a “black box” warning – the strongest warning the Food and Drug Administration issues – for its risk to the kidneys. It’s also not recommended for people older than 65.
We sometimes use an off-label prep that’s basically MiraLAX dissolved in 64 ounces of Gatorade. It’s still a lot to drink, but it tastes better.
We ask that you do a split prep, which means you drink half the night before and the other half six hours before the procedure. I know this can be annoying if your procedure is at 8 a.m. and you need to get up at 1 or to finish the drink, but you’ll get a more thorough cleansing.
How to make your colonoscopy prep easier
I know this process isn’t fun. But it’s important, and there a few things you can do to make it a little easier:
- Listen to your doctor’s instructions: Take notes and ask questions if you don’t understand something.
- Arrange your schedule: You’ll want to be home – and in your own bathroom – during colonoscopy prep. If you have children, find someone to help care for them while you’re indisposed.
- Cut back on fiber a couple days beforehand: Fiber is the indigestible part of plant foods and leaves a high amount of residue in the colon. Stick to a low-fiber diet, and avoid foods such as:
- Beans
- Nuts
- Raw fruits and vegetables
- Whole grains
- Maintain a liquid diet: Water gets boring pretty quickly. Have a few other options on hand.
- Clear broth
- Coffee or tea
- Italian ice
- Jell-O
- Popsicles
- Drink your prep: Some of these solutions don’t taste great, but as mentioned, it’s the most important part of the prep process.
- Add flavoring such as Crystal Light or Kool-Aid powder if the prep isn’t flavored.
- Drink it cold.
- Use a straw.
- Suck on a lemon or hard candy afterward.
- Prepare the bathroom: Once the prep solution starts working, you’ll want to stay close to a bathroom.
- Wear loose clothing.
- Stock up on soft toilet paper.
- Use skin-soothing products such as baby rash ointment.
- Keep entertainment handy; you may be there a while. This could include books, a laptop or a tablet.
Finally, remember that this screening could save your life. Excluding skin cancers, colorectal cancer is the third most common cancer diagnosed in the United States, with more than 135,000 cases expected to be diagnosed in 2017.
When should you be screened for colon cancer?
The U.S. Preventive Services Task Force recommends that people at average risk for colorectal cancer begin screening at age 50.
Your doctor may recommend starting before age 50 if you have factors that put you at increased risk, such as:
