Magnesium Citrate Bowel Prep Instructions for Colon Surgery
These instructions are for patients preparing for colon surgery with Dr. Aisha Akhtar, a board-certified colon and rectal surgeon in Phoenix, Arizona.
Please follow the instructions given directly by our office. Medication holds, bowel preparation timing, antibiotics, and day-of-surgery instructions may be adjusted based on your medical history and surgical plan.
Important: This page is based on colon surgery preparation instructions. Do not use these instructions for a routine colonoscopy unless our office specifically tells you to do so.
Clear liquid diet
The day before your procedure, you will start a clear liquid diet at the time instructed by our office.
Clear liquids may include:
- water
- coffee or tea without milk or cream; sugar is acceptable
- soft drinks such as 7UP, Sprite, orange soda, or ginger ale
- Gatorade or Powerade
- Kool-Aid
- strained fruit juices without pulp
- sparkling water
- chicken, beef, or vegetable broth or bouillon
- hard candies
- Jell-O without fruit or toppings
- popsicles
Do not drink or eat anything colored red or purple. Any other flavor is acceptable unless our office gives you different instructions.
Medications to stop 7 days before surgery
You may need to stop the following medications and supplements 7 days before surgery, unless our office gives you different instructions:
- GLP-1 medications, including semaglutide, tirzepatide, and dulaglutide
- ibuprofen
- NSAIDs
- gout medications
- glucosamine/chondroitin
- vitamin E
- ginseng
- St. John’s wort
- black cohosh
- garlic supplements
- herbal supplements
Do not stop prescribed medications unless instructed by Dr. Akhtar, your prescribing clinician, or the surgical team.
Medications to stop 5 days before surgery
You may need to stop the following medications 5 days before surgery:
- aspirin
- Coumadin/warfarin
- Plavix/clopidogrel
If you take Coumadin/warfarin or Plavix/clopidogrel, speak with your prescribing physician before stopping these medications.
Diabetes medication instructions
If you use insulin, follow the individualized instructions provided by your surgical team.
For Metformin/Glucophage, do not take it the night before your procedure or the morning of your procedure, unless our office gives you different instructions.
Medications on the day of surgery
On the day of your procedure, do not take diuretics, including:
- Lasix/furosemide
- hydrochlorothiazide
- Aldactone/spironolactone
- Diovan HCT
On the day of your procedure, do take your heart or blood pressure medications, unless you were given different instructions.
Magnesium citrate bowel preparation
The afternoon before your procedure, you will perform bowel preparation to clear out the bowel.
Magnesium citrate is purchased over the counter and does not require a prescription.
You will need:
- 2 bottles of magnesium citrate, 10 ounces each
- magnesium citrate that is not red or purple
- at least 4 Dulcolax tablets
Bowel prep schedule
2:00 PM
Drink the first 10-ounce bottle of magnesium citrate over 30 minutes.
3:00 PM
Take 2 Dulcolax tablets by mouth.
5:00 PM
Drink the second 10-ounce bottle of magnesium citrate over 30 minutes.
6:00 PM
Take 2 Dulcolax tablets by mouth.
6:00 PM to 10:00 PM
Drink at least 32 ounces of clear liquids.
Antibiotics and nausea medication
You will need to take two antibiotics the day before your procedure.
Neomycin
Take neomycin 500 mg, 2 tablets by mouth at:
Metronidazole
Take metronidazole 500 mg, 1 tablet by mouth at:
Taking antibiotics on an empty stomach can sometimes cause nausea. Our office may also prescribe nausea medication for you to keep available if needed.
Ondansetron/Zofran
Take ondansetron/Zofran 4 mg by placing 1 tablet on the tongue and allowing it to dissolve.
You may take this every 6 hours as needed for nausea.
Bathing before surgery
It is recommended that you bathe the night before and the morning of your procedure to help lower the risk of infection.
The preferred soap is HIBI-CLENS or chlorhexidine gluconate, also called CHG. This can usually be purchased at most pharmacies. You will need at least a 4-ounce bottle.
If you are unable to obtain HIBI-CLENS, you may use an antibacterial soap such as Dial, Lever, or Safeguard. Body wash or bar soap is acceptable.
When bathing:
- wash from the neck down
- leave the soap on your skin for 3 to 5 minutes before rinsing
- do not wash with your regular soap after using the antibacterial soap
Morning of surgery reminders
The morning of your procedure:
- do not shave the surgery site
- bring your rescue inhaler if you use one
- if you use an insulin pump, leave it on and bring your pump supplies
- if you use a CPAP or BiPAP machine, you may be asked to bring it with you
- do not wear contact lenses
- do not wear makeup
- remove all colored nail polish
- do not wear jewelry
- do not apply lotions, perfumes, powders, or deodorant after using the antibacterial soap on the day of surgery
- wear casual, comfortable, loose-fitting clothes
- you may be asked to remove dentures before surgery; the hospital will provide a denture cup and return them after surgery
Surgery center call
If you have not heard from the surgery center by noon the day before your procedure, please call our office.
When to call the office
Please contact the office if:
- you are unsure whether these instructions apply to you
- you cannot tolerate the bowel prep
- you vomit repeatedly after starting the prep
- you did not have bowel movements after taking the prep
- you have questions about magnesium citrate, Dulcolax, antibiotics, or nausea medication
- you have questions about blood thinners, diabetes medications, GLP-1 medications, diuretics, or heart medications
- you have kidney disease and were not specifically instructed to use magnesium citrate
- you have not heard from the surgery center by noon the day before surgery
- you develop fever, severe abdominal pain, chest pain, shortness of breath, or worsening weakness
Request an Appointment
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Frequently Asked Questions
Is this magnesium citrate prep for colonoscopy or colon surgery?
These instructions are for colon surgery preparation. They include antibiotics, bathing instructions, and surgery-specific reminders. Do not use this as routine colonoscopy prep unless our office specifically instructs you to do so.
Do I need a prescription for magnesium citrate?
No. Magnesium citrate is usually purchased over the counter. You will need two 10-ounce bottles unless our office gives you different instructions.
Can I use red or purple magnesium citrate?
No. Do not use magnesium citrate that is red or purple.
When do I take Dulcolax?
Take 2 Dulcolax tablets at 3:00 PM and 2 Dulcolax tablets at 6:00 PM, unless our office gives you different instructions.
Do I need antibiotics before surgery?
Yes, if prescribed as part of your colon surgery prep. The listed antibiotics are neomycin and metronidazole, taken the day before surgery.
What should I do if the antibiotics make me nauseated?
Our office may prescribe ondansetron/Zofran. Take it as directed if nausea occurs.
Should I stop my blood thinners?
Do not stop blood thinners without guidance. If you take Coumadin/warfarin, Plavix/clopidogrel, aspirin, or another blood thinner, confirm the plan with your prescribing clinician and surgical team.
