December 01, 2018

Do I have to drink a large amount of laxative solution before a colonoscopy?

Q: Among the discomforts of having a colonoscopy, the worst for me is drinking the large amount of laxative solution in preparation. Are there ways to avoid this?

A: Colonoscopy can be a lifesaving screening test for colon cancer. However, one often uncomfortable aspect is that the large intestine needs to be empty and clean in order for the procedure to be most effective. There's no way to avoid some type of bowel cleansing product to make this happen.

Until fairly recently, the main bowel prep product involved drinking 2 to 4 liters — or 64 to 128 ounces — of somewhat salty tasting fluid over a short time. However, several new products have been developed in the past decade that involve drinking significantly less fluid.

  • Prepopik comes in a 10-ounce dose, which you drink along with 64 ounces of a clear liquid of your choice.
  • Suprep comes in a 12-ounce dose, which you drink along with 84 ounces of a clear liquid.
  • Plenvu — the latest product — comes in a 32-ounce dose, which you drink in addition to at least 32 ounces of a clear liquid.

There's also a nonprescription option that involves using polyethylene glycol (Miralax) followed by an electrolyte-containing drink such as Gatorade. However, it doesn't work as effectively as prescription preparations, and depending on your medication coverage, might actually cost more.

With any colon prep laxative, a "split dose" is often recommended. This involves drinking just half of the laxative in one sitting, with the other half taken later in the day or the morning of the procedure. This can help make even high-volume bowel...