Medically Reviewed on 8/25/2023

Brand Name: Colyte

Generic Name: peg-3350 and electrolytes

Drug Class: Laxatives, Osmotic

What is Colyte, and what is it used for?

Colyte is a prescription medicine used to clean the colon before a colonoscopy or barium enema X-ray examination. Colyte cleans your colon by causing you to have diarrhea. Cleaning your colon helps your healthcare provider see the inside of your colon more clearly during your colonoscopy or barium enema X-ray examination.

It is not known if Colyte is safe and effective in children.

What are the side effects of Colyte?

Colyte can cause serious side effects, including:

  • changes in certain blood tests. Your healthcare provider may do blood tests after you take Colyte to check your blood for changes. Tell your healthcare provider if you have any symptoms of too much fluid loss, including:
  • ulcers of the bowel or bowel problems (ischemic colitis). Tell your healthcare provider right away if you have severe stomach-area (abdomen) pain or rectal bleeding.

The most common side effects of Colyte include:

  • nausea
  • stomach-area (abdomen) fullness and bloating

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of Colyte. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the dosage for Colyte?

Colyte with flavor packs can be administered orally or by nasogastric tube. Patients should fast at least 3 hours prior to administration.

A one-hour waiting period after the appearance of clear liquid stool should be allowed prior to examination to complete bowel evacuation. No foods except clear liquids should be permitted prior to examination after Colyte with flavor packs administration.


The recommended adult oral dose is 240 mL (8 fl. oz.) every 10 minutes. Lavage is complete when fecal discharge is clear. Lavage is usually complete after the ingestion of 3 - 4 liters (3 – 4 quarts).

Nasogastric Tube

Colyte with flavor packs is administered at a rate of 20 - 30 mL per minute (1.2 - 1.8 L/hour).

Preparation of Colyte with flavor packs Solution:

This preparation can be used with or without the flavor packs.

  1. To add flavor, tear open one flavor pack at the indicated marking and pour contents into the bottle BEFORE reconstitution. Discard unused flavor packs.
  2. SHAKE WELL to incorporate flavoring into powder.
  3. Add tap water to FILL line. Replace cap tightly and mix or shake well until all ingredients have dissolved. (No other additional ingredients, e.g. flavorings, should be added to the solution.)

Note: If not using flavor packs, omit steps one and two above.


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What drugs interact with Colyte?

Drugs That May Increase Risks Due to Fluid and Electrolyte Abnormalities

  • Use caution when prescribing Colyte for patients with conditions, or who are using medications, that increase the risk for fluid and electrolyte disturbances or may increase the risk of adverse events of seizures, arrhythmias, and prolonged QT in the setting of fluid and electrolyte abnormalities.
  • Consider additional patient evaluations as appropriate in patients taking these concomitant medications.

Potential for Altered Drug Absorption

  • Oral medication administered within one hour of the start of administration of Colyte may be flushed from the gastrointestinal tract and the medication may not be absorbed properly.

Pregnancy and breastfeeding

  • It is not known whether Colyte can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity.
  • Colyte should be given to a pregnant woman only if clearly needed. It is not known whether this drug is excreted in human milk.
  • Because many drugs are excreted in human milk, caution should be exercised when Colyte is administered to a nursing woman.


Colyte is a prescription medicine used to clean the colon before a colonoscopy or barium enema X-ray examination. Colyte cleans your colon by causing you to have diarrhea. Serious side effects of Colyte include changes in certain blood tests, ulcers of the bowel, or bowel problems (ischemic colitis).

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Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 8/25/2023
All sections courtesy of the U.S. Food and Drug Administration