How to make your colonoscopy prep better

Clear liquid diets, giant containers of prep solution, heightened nerves, and spending the majority of an evening tied to your toilet — it’s no wonder that for many people, the toughest part of a colonoscopy isn’t the procedure itself: it’s the preparation.

As a gastroenterologist at UT MD Anderson, screening patients for colorectal cancer is one of my most important tasks. But a colonoscopy is really a partnership. Your care team doesn’t do all the work; you do much of it ahead of time.

Here are some of the best tips I’ve learned over the years to make the bowel prep process easier.

Know your ‘why’

While prepping for a colonoscopy can be unpleasant, it’s helpful to understand exactly why you need it.

Colonoscopies are the best colorectal cancer screening method we currently have. They can help your care team find and detect colorectal cancer at an earlier stage, when it’s easier to treat.  

But colorectal cancer isn’t the only thing we look for. This procedure allows us to see any abnormalities in your colon. These may include:

• Polyps, or growths in the colon’s lining
• Inflammation
• Ulcers, or lesions caused by medications or other illnesses
• Bacterial or viral infections
• Diverticula, or little pockets in the lining that can become inflamed or infected  
• Hemorrhoids, or bundles of veins just inside the anus that can become swollen and painful

During a colonoscopy, a gastroenterologist uses a scope to carefully examine the inside of your colon, which normally looks like a collapsed tube sock. Your doctor uses air to gently stretch it out so they can see inside any folds or crevices.

For a doctor to get a really good look at your colon, though, it needs to be clean. Just like a dirty window makes it hard to get a clear view of what’s outside, lingering stool and food material can make it harder for your doctor to get a good look at the walls of your colon.

Start preparing early

Preparing for a colonoscopy is very similar to following a recipe. But you want to check the recipe before you actually cook the meal. This ensures you’ll have all the ingredients on hand, understand the directions and know exactly how long the process will take.

If you wait until the day before your colonoscopy, it may be too late to start preparing. So, set aside some time about a week ahead of your procedure to read the instructions, pick up your prep materials and ensure you’ll have everything you need.

If you follow the prep instructions carefully, getting a colonoscopy usually isn’t as bad as you may have heard. I think sometimes the hype is worse than the actual experience. Usually, people wake up from their procedures with me saying, “Wow, that wasn’t that bad!”

Eat a low-fiber diet the week before your colonoscopy

A week before your colonoscopy is a good time to start eating a low-fiber diet. While fiber is good for you, it can stick around your colon and gastrointestinal tract. That’s why you should avoid high-fiber foods such as raw vegetables and salads starting about a week before your procedure.

Stick to a clear liquid diet the day before your colonoscopy

Avoid solid foods and follow a clear liquid diet the day before your procedure.  

While the term “clear liquid” might sound like it means only water and broth, it actually includes anything you could put into a shallow glass dish and still read a newspaper through. For example, you can eat and drink options like:

• Black coffee
• Sports drinks
• Gelatin desserts
• Broth that doesn’t contain anything fibrous, like rice, bread or vegetables.

Avoid food and drinks with red, orange and purple food coloring

Steer clear of anything with red, orange or purple food coloring the day before your procedure, though. This is because it can be hard for your care team to tell the difference between those reddish food dyes and something like blood or inflammation in your colon.

Foods and drinks with green or blue coloring are totally fine. If I see green in your colon, for example, I won’t confuse it with blood. It’s more of a concern with those reddish colors.

Pick your prep

If you think an enormous jug of flavored liquid is the only way to prepare for a colonoscopy, I have some good news for you: there are now other options. Some involve slightly less fluid to drink — while others involve pills and plain water instead of a powdered mix. Here is a breakdown of the current products available.

Higher-volume liquid

The oldest type of prep is called GoLytely. It’s a flavored powder containing a chemical compound called polyethylene glycol (PEG). You mix it with four liters (or a little less than a gallon) of water and drink it.

Lower-volume liquid

Newer products, such as MoviPrep, PLENVU, CLENPIQ and SuPrep, are also flavored powders containing polyethylene glycol. But they require you to mix them with only about half as much water to achieve the same results.

MiraLAX has a lower-volume colon prep mix available, too, though it must often be followed by additional fluids and is sometimes supplemented with four stool softener pills.

Pills and plain water

If you can’t stand those flavored powdered mixes, how about some pills and plain water instead?

SuTab is a relatively new form of colon prep that uses three mineral salts — sodium sulfate, magnesium sulfate and potassium chloride — to pull water into your colon and flush out its contents. But instead of mixing them with water, you swallow them whole in pill form (two batches of 12), along with the recommended amount of liquid. This liquid can be plain water, a sports drink, or any other type of colonoscopy-friendly beverage you want. It’s really up to you.

There’s no such thing as a fluid-free colonoscopy prep

The most important thing to remember here is that you really can’t get away from ingesting some amount of liquid. There’s no such thing as a fluid-free colon prep. So, please don’t think you can just swallow the pills and then skimp on the liquid. If you do that, you will not have a good result, and you’ll likely have to repeat your prep.

It’s also important to talk to your doctor about which option they’d recommend specifically for you, based on your medical history and any medications you’re taking.  

This is because magnesium- and phosphate-based preps can be problematic for patients with kidney disease. And, there’s a higher incidence of nausea and vomiting with the pills than with other forms of colon prep. The pills are also quite large. So, if you’re already struggling with any of those issues — or you have problems swallowing — a pill-based option might not be the best choice.     

Don’t drink your prep solution all at once

If you do opt for a solution-based prep protocol, keep in mind that there are many different varieties and flavors to choose from. They all work in a similar way, though, and involve some type of powder that you mix with a lot of water.

One common misconception about the prep solution is that you are supposed to drink it all at once.  

Instead, at UT MD Anderson, we recommend a more effective way to clean your colon called a split-dose prep. This means drinking half the prep the night before your procedure — usually within about a two-hour window — and saving the other half for the morning of your procedure. Usually, we aim to have patients finish the second half of their prep about four hours before the colonoscopy.

Chill your prep solution

One easy way to make your prep solution taste better? Drink it cold. Lukewarm prep in a jug that's been sitting out is going to taste much worse than if it’s ice cold.

If the jug is too big to fit in your fridge, fill a thermos with ice and pour your prep into it as you drink it.

Use a straw to drink your prep

Using a straw can block some of the prep solution’s flavor and make drinking it easier. Win-win!

Flavor your prep solution your way

Some prep solutions come with a flavoring packet. While these flavoring packets may make your prep taste better, they don’t make your prep work any better.

You don’t need to use the flavoring packet that comes with your prep. Instead, you can go without or use another option like flavored electrolytes or lemonade packets — just be sure to avoid options with red food coloring.

One perk of using electrolyte packets is that they can help you stay hydrated. Prepping for a colonoscopy means drinking lots of fluid — and flushing lots of fluid out of your body. Electrolyte packets can help you stay hydrated without having to drink even more water.

Put a menthol candy under your tongue while drinking prep

One lesser-known tip for getting through your prep? Place a menthol candy under your tongue to block the prep’s taste. Just remember to choose an option without red, orange or purple food dye.

Remember the bigger picture

Preparing for your colonoscopy can feel more inconvenient than the actual procedure. But if it’s too unpleasant, we know you won’t do it. So, we try to make it easy, but also safe.

The colonoscopy itself is a relatively quick procedure. It only takes about 30 to 40 minutes. Most of that time, you’ll be asleep under anesthesia.  

A colonoscopy is also painless, since you don’t have any nerves in your colon. Even getting polyps removed doesn’t hurt. You’ll wake up completely unaware of what you’ve just been through. The most you might feel is a little gassy, due to the air used to inflate the colon.

You usually don’t have to get a colonoscopy all that frequently, either. If you’re at average risk for colorectal cancer, you should get a colonoscopy every 10 years starting at age 45. If polyps are found, you may need another colonoscopy a little sooner.

But if we don’t find anything or the findings are benign, you only need a colonoscopy every 10 years. At UT MD Anderson, we strive to give you a high-quality exam every time so that we don’t have to repeat your colonoscopy more often than necessary. Better prep leads to a higher quality exam, so it’s worth your while to follow the instructions carefully.

Lavanya Viswanathan, M.D., is a gastroenterologist who specializes in motility disorders at UT MD Anderson.

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