Colonoscopy Prep: Instructions, Types and Expectations

Polymer-based formulas are the most commonly used type of colonoscopy prep. They get their name from the active ingredient of polyethylene glycol 3350 (PEG), a large molecule that the colon can't absorb. PEG triggers your digestive system to release water, resulting in bowel movements. PEG laxatives are most often powders that are mixed into water to drink.

PEG Drink Names

Your colonoscopy prep paperwork will indicate the type of laxative your doctor has ordered.

The following are names for PEG laxatives:

• GoLYTELY
• CoLyte
• NuLYTELY
• TriLyte
• MiraLAX
• Halflytely
• GaviLyte
• MoviPrep

Pros of PEG laxatives

PEG laxatives are the most common because they are well-tolerated by most people. They’re also safer for people with certain medical conditions, such as kidney disease and heart disease.

Cons of PEG laxatives

The primary con of a PEG laxative is that it comes as a powder that must be mixed into high volumes of water. To take it correctly, you may need to drink as much as 4 liters of water.

Risks

If you’re not able to drink the full amount of the laxative, there’s a risk the colonoscopy screening will be less effective.

Saline-based formulas use a form of salt called sodium phosphate (NaP) and other mineral salts to draw water out of the intestines and into a bowel movement.

Saline-Based Names

Saline-based colonoscopy prep is known as:

• Clenpiq
• Suprep
• Prepopik
• Visicol
• OsmoPrep
• SUTAB

Pros

Saline-based laxatives can be taken by mouth as a tablet, which makes them easier for some people to tolerate.

Cons of Saline-Based Formulas

Saline-based laxatives can irritate the sensitive mucosa (lining) of the intestines, especially for people with any kind of gastrointestinal disease. They're also more likely to cause electrolyte imbalances.

Risks

The risks of using a saline-based formula include:

• Imbalance of potassium, sodium or phosphate
• Kidney damage
• Low calcium
• Low magnesium
• Dehydration
• Seizures

Let your doctor know about any medical conditions you have. You may be more at risk for complications if you have irritable bowel disease (IBS), kidney or liver disease, a heart condition, diabetes, already take diuretics or are over the age of 65.

Most people can tolerate colonoscopy prep, but always discuss any specific concerns you have with your doctor. Your provider can help you choose the best type of prep for you.

There are also variations of the most common types of colonoscopy prep, such as more concentrated, lower-volume mixes, that can be used.

GLP 1 medications need to be held for one week prior to the procedure. If you are on anticoagulants (Warfarin, Lovenox, Eliquis) or antiplatelet medications such as Plavix, these will need to be held prior to the procedure. Please contact your doctor for specific instructions.

Fill your bowel prep prescription and carefully review the instructions. Your colon must be fully cleared of solid matter so your doctor can see clearly. Your exam may be cancelled if your colon isn’t clean.

• Don’t eat any fibrous foods, such as raw fruits, raw vegetables, seeds, nuts or dairy.
• Stop taking iron or fiber supplements.
• Organize a ride home.

Don’t eat any solid foods. Begin a clear liquid diet in the morning. Clear foods and liquids include:

• Water
• Apple juice
• Sprite
• Ginger ale
• Gatorade (avoid red or purple)
• Popsicles or jello (avoid red or purple)
• Clear soup broth
• Coffee or tea (avoid milk or creamer)
• Hard candy (avoid red or purple)

Drink at least eight glasses of water or clear liquids. Avoid any red or purple liquids.

• Start bowel prep according to the instructions.
• Hydrate during and after prep.

• Follow instructions for the next dose of prep five hours before your exam. You may have to wake up very early if your procedure is in the morning.
• Don’t eat or drink anything, or your exam may be cancelled.
• Your stool should be clear yellow liquid.

• Don’t eat or drink anything, or your exam may be cancelled.
• Arrive for your exam at least one hour before your appointment.

Polymer-based formulas are the most commonly used type of colonoscopy prep. However, many people find these nauseating. The pill form of saline-based solutions is easier for some people to tolerate, but they can irritate the intestinal lining. Speak to your doctor to determine which prep is best for you.

Most people do fine with colonoscopy preparation. However, if the preparation is causing nausea, try drinking through a straw, washing your mouth out afterward or sucking on a hard candy. If you vomit, wait 30–60 minutes before trying again. Contact your provider if you can’t complete the prep.

Talk to your doctor about approved medication. You can take aspirin, blood pressure medication, prednisone or other steroids before a colonoscopy. You may need to pause weight loss medications, such as GLP-1, before the procedure, so read your doctor's instructions carefully.

You’ll begin having frequent bowel movements that will become watery and yellow. By the end of the prep, your stool should be clear or light yellow, with no solid pieces.

Call your doctor if you can't finish the prep. Incomplete prep may lead to:

• Rescheduling the procedure
• Missed polyps or findings
• Additional costs or delay in care

Frequent bowel movements can cause irritation. Try the following:

• Use soft toilet paper or unscented wipes
• Apply petroleum jelly or diaper cream to the area
• Take short breaks between prep doses

• Bring an adult (18 or older) to drive you home. You can take a cab, medical transport or bus only if an adult is riding with you after your visit.
• Bring a list of all medications you take, including over-the-counter ones and vitamins.
• Bring your insurance card.