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Magnesium Citrate Bowel Preparation

Learn how to use magnesium citrate for an effective afternoon colonoscopy prep. Follow expert guidelines for a smooth, successful procedure.

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Texas Medical Board
Harris County Medical Society
American College of Gastroenterology
American Society for Gastrointestinal Endoscopy
Memorial hermann
Houston Methodist leading Medicine
HCA Houston Healthcare

Video Instructions

Written Instructions

General Instructions

2 Weeks Before the Procedure

Foods No change
Liquids Drink plenty of water
Medications Hold - GLP1 Agonist Medication:
  • Dulaglutide (Trulicity)
  • Exenatide (Byetta)
  • Exenatide Extended Release (Bydureon BCise)
  • Liraglutide (Victoza)
  • Lixisenatide (Adlyxin)
  • Semaglutide (Ozempic, Wegovy, Rybelsus)
  • Tirzepatide (Mounjaro)

1 Week Before the Procedure

Foods

No Nuts or Seeds - berries, cashews, corn nuts, peanuts, pecans, popcorn, walnuts

Low Fiber Diet

  • Foods - white bread, cheese, eggs, yogurt
  • Soups - clear vegetable, chicken or beef broth
  • Vegetables - cooked without skin like mashed potatoes
  • Fruits - pureed fruits without skin like applesauce
Liquids Drink plenty of water
Medications
  • Take as usual unless otherwise instructed
  • Hold - Anti-Diarrheal Medication - Imodium, Kaopectate, Pepto-Bismol
  • Hold - Iron Tablets
  • Hold - Multivitamins

Pharmacy

  • Fill or buy preparation medication
  • Pick up 3 days before your procedure

1 Day Before the Procedure

Foods
  • Clear Liquid Diet
  • Soups - clear vegetable, chicken or beef broth
  • Juices - clear only without pulp
Liquids
  • Drink plenty of water
  • No alcohol
  • No red or purple colored drinks
Medications
  • Hold - Oral Diabetes Medication
  • Insulin - Take ½ the dose the entire day
  • Blood Pressure Medication - The pre-anesthesia team (PAT) will instruct you on how to take your blood pressure medications.
  • All other medications - continue as normal

Procedure Day

Foods No food or liquids the day of the procedure

Medication Instructions

Attention

Expected Symptoms Do not stop the bowel preparation
  • Abdominal Pain
  • Bloating
  • Cramps
  • Diarrhea
  • Gas
  • Nausea

First Dosage → 10PM - 12AM

Step 1 10PM - 11PM

Drink 1st 10 ounce bottle of Magnesium Citrate

Step 2 11PM - 12AM

Drink 16 ounces of water

Second Dosage → 4AM - 6AM

Step 1 4AM - 5AM

Drink 2nd 10 ounce bottle of Magnesium Citrate

Step 2 5AM - 6AM

Drink 16 ounces of water

12AM

Foods No food or liquids after midnight except prep solution

Frequently Asked Questions

How to take magnesium citrate for bowel prep?

Drink the full bottle (10 oz) of magnesium citrate, followed by at least 8 ounces of clear liquid. Stay hydrated and expect frequent bowel movements within a few hours.

How long does it take to empty bowels after magnesium citrate?

Bowel movements typically start within 30 minutes to 6 hours. The cleansing process continues until stool is clear, usually requiring multiple trips to the bathroom.

Why is magnesium citrate no longer used for colonoscopy prep?

Magnesium citrate is less effective than newer bowel preps and poses risks of electrolyte imbalance, dehydration, and kidney issues, especially in older adults or those with health conditions.

How much magnesium citrate to clean out bowels?

A full 10 oz bottle is typically recommended, but some cases may require a second dose. Always follow your doctor's instructions and drink extra fluids to stay hydrated.

When is the best time to take magnesium citrate?

Take it in the evening before your colonoscopy, around 4 PM-6 PM, ensuring enough time for bowel movements to clear the intestines before the procedure.

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