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Patient Instructions · United Gastroenterology Associates
Plenvu Colonoscopy Prep Instructions
At United Gastroenterology Associates in Cypress and Katy, Plenvu is used as a low-volume, split-dose bowel prep: Dose 1 the evening before your colonoscopy and Dose 2 4 hours before you leave home on the day of your procedure, each followed by 32 ounces of clear liquid. When you start Dose 1 depends on your arrival time. Follow the practice’s step-by-step instructions below, read the General Colonoscopy Instructions first, and call (346) 340-4414 with any questions. These instructions are for patients scheduled with Muhammad Ali Khan, MD, FACP, FASGE, at United Gastroenterology Associates.
Medically reviewed by Muhammad Ali Khan, MD, FACP, FASGE · Updated
Prep questions: (346) 340-4414
Plenvu Prep at a Glance
Dr. Khan's Plenvu instructions use two doses. Start Dose 1 between 3 and 6 PM if your arrival time is before 9:00 AM, or between 6 and 8 PM if your arrival time is after 9:00 AM. Mix the Dose 1 pouch with 16 ounces of water, drink it within 30 minutes, then drink 32 ounces of clear liquid over the next 30 to 60 minutes. Four hours before you leave home, mix Dose 2 (pouch A and pouch B) with 16 ounces or more of water, drink it within 30 minutes, then drink 32 ounces of clear liquid over the next 30 to 45 minutes. Stop everything by mouth 3 hours before your arrival time, and follow these instructions rather than the instructions on the box.
Important
Follow the instructions given to you by your doctor. Do not stop, start or change any medicine unless Dr. Khan's office or your prescribing doctor tells you to. If the instructions you received differ from this page, follow the instructions you received.
Have DIABETES? Read this first!
Plenvu Prep
IMPORTANT GLP-1 DRUG INFO
The following weight loss / diabetic drugs should be held as instructed prior to procedure:
- Liraglutide: Victoza (weekly) and Saxenda (daily)
- Dulaglutide: Trulicity (weekly)
- Exenatide: Bydureon (weekly) and Byetta (daily)
- Semaglutide: Ozempic (weekly), Wegovy (weekly) and Rybelsus (daily)
- Tirzepatide: Mounjaro (weekly) and Zepbound (weekly)
- Lixisenatide: Adlyxin (daily)
The medication will need to be stopped seven (7) days prior to your procedure if you are on a weekly dose or the day of your procedure if you are on a daily dose.
5-7 Days before your procedure
Have your prescription filled. Please follow the prep instructions listed below, not the instructions on the prep box. Questions about the procedure itself? See our colonoscopy services overview, or call the Katy office or Cypress office.
5 Days before your procedure
If you routinely have less than 2 bowel movements per week then you will also need to purchase an 8.3 oz. bottle of Miralax. Begin taking a dose of Miralax twice a day 5 days prior to your procedure. Take the last dose of Miralax in the morning the day before your procedure.
3 Days before your procedure
AVOID raw fruits and vegetables, whole wheat/multigrain products, beans, nuts, popcorn and seeds.
1 Day before your procedure
You may only have clear liquids the entire day such as water, coffee, tea, broth, sodas, apple juice, Gatorade, Kool-aid, Jell-O, popsicles and hard candy. You may not have any solid food. It is important to drink extra clear liquids before your prep to maintain adequate hydration. Do not drink liquids that are not clear such as milk. Do not drink liquids that are red or purple in color.
The day before the procedure start your prep – Pay attention to start times listed
If your appointment arrival time is before 9:00 AM please take your first dose of prep between 3-6 pm
If your appointment arrival time is after 9:00 AM please take your first does of the prep between 6-8 pm
STEP 1:
- Use the mixing container to mix the contents of the Dose 1 pouch with 16 ounces of water and stir/shake until completely dissolved. This may take up to 2-3 minutes. The prep may be mixed up to 6 hours prior to your prep start time if refrigerated. Drink the entire contents within the next 30 minutes. A straw may help.
STEP 2:
-
- Refill your mixing container with 32 ounces of clear liquid and drink within the next 30 -60 minutes.
- Make a conscious effort to drink as much clear liquids as you can before, during and after the preparation.
- If you experience nausea – slow down your prep intake and walk around until nausea is relieved.
- Use baby wipes and/or Balneol cleansing cream or lotion during the prep to reduce irritation.
The day of the procedure – 4 HOURS before you leave home for your appointment
-
STEP 1:
Use the mixing container to mix the contents of the Dose 2 (Pouch A and Pouch B) with 16 ounces or more of water and stir/shake until completely dissolved. This may take up to 2-3 minutes. Drink the entire contents within the next 30 minutes. A straw may help. STEP 2:- Refill your mixing container with 32 ounces of clear liquid and drink within the next 30 -45 minutes. You may continue to drink clear liquids at your own pace until 3 hours before your appointment arrival time.
- You may take your prescription medications (except those listed in the booklet) with water up to 3 hours before your appointment arrival time.
- Do not use smokeless tobacco on the day of your procedure. Starting 3 hours before your appointment arrival time absolutely nothing by mouth, including gum, hard candy, and breathe mints.
Please call us at (346) 340 4414 if you have any questions or if you are having difficulty with the preparation. We are available 24 hours a day, 7 days a week.
Make An AppointmentDiabetic Prep
Medications
- If you take oral medications for your diabetes, do NOT take your diabetes pills on the day prior to your procedure (prep day) or on the day of your procedure (until your procedure is complete and you resume a normal diet).
- If you take non-insulin injectable medications (Byetta, Bydureon, Victoza, Trulicity, Tanzeum, Symlin), do not take the medication if your injection day is the day prior to your procedure (prep day). You can resume it after the procedure is complete.
- If you take insulin, reduce your dose by 50% (half) of your normal dose on the day prior to your procedure and the day of your procedure. You can resume your normal dose after the procedure when you resume normal diet.
- If you use an insulin pump, contact your diabetes doctor for instruction. Generally, most patients will need to reduce their basal rate to 80% of the normal rate.
Diet
- You should aim for 45-60 grams of carbs with each meal. Although you may ordinarily avoid sugars, they are ok to take when you are prepping for your colonoscopy as these will be the main source of calories when you are on a clear liquid diet.
- For snacks, try to include other fluids that contain electrolytes such as broth.
- Examples of clear liquids with carb amounts are listed below. Note, if you experience low blood sugar (<60) during the 2 hours before your procedure, you can take 3 teaspoons of soda or clear juice to raise your sugar. Do NOT take solid foods or non-clear liquids, as your procedure will be cancelled.
FLUID
AMOUNT
CARBS
Juice
1/2 cup
15 g
Jello
1/2 cup
15 g
Soda
1 can
40 g
Popsicle
1 double stick
15 g
Gatorade/Powerade
1/2 cup
15 g
Broth (veg/chicken/beef)
any
0 g
Clear Protein Drinks
Clear Protein Drinks
0 g
Please call us at (346) 340 4414 if you have any questions or if you are having difficulty with the preparation. We are available 24 hours a day, 7 days a week.
Make An AppointmentKey Rules From the General Colonoscopy Instructions
These points summarize the general colonoscopy instructions from Dr. Khan and his team. Read the full general colonoscopy instructions for details, and follow any personal instructions the office gives you.
- Driver: an adult must drive you home and stay at the center during your procedure.
- Blood thinners: ask the office for guidance before your procedure. Do not stop them on your own.
- GLP-1 medicines: tell the office if you take one. The instructions give separate timing for weekly and daily GLP-1 medicines.
- Iron, diet pills and herbal medicines: the instructions ask you to stop these 7 days before.
- Alcohol: avoid for 24 hours before and after your colonoscopy.
- Before arrival: nothing by mouth starting 3 hours before you arrive, except approved medicines with up to 2 tablespoons of water.
- Rescheduling: call at least 3 to 4 days ahead.
Tell the office before your prep if you
- Take a blood thinner or aspirin
- Have diabetes or take insulin
- Take a GLP-1 medicine
- Have kidney or heart disease
- Are pregnant or may be pregnant
These conditions can change how you prepare. The office will give you personal instructions.
Questions About Your Plenvu Prep?
If you are unsure about your prep, your medicines or your arrival time, call the office before you start.
If Your Plenvu Prep Is Not Working
Most preps start working within one to three hours of the first dose. If nothing has happened several hours after your first dose, if you are vomiting and cannot continue, or if your stool is still brown after the second dose, call (346) 340-4414 before your procedure. Read what to do if your colonoscopy prep is not working, what you can eat before a colonoscopy and low-residue foods before a colonoscopy. For the procedure itself, see colonoscopy services in Katy and Cypress.
Plenvu Prep FAQs
Answers to common questions from patients preparing for a colonoscopy with Plenvu.
What is Plenvu?
Plenvu is a low-volume prescription bowel prep made of polyethylene glycol 3350 (PEG-3350), sodium ascorbate, sodium sulfate, ascorbic acid, sodium chloride and potassium chloride. The kit contains a Dose 1 pouch, a Dose 2 pouch A and pouch B, and a mixing container.
When do I take each Plenvu dose?
If your arrival time is before 9:00 AM, take Dose 1 between 3 and 6 PM the day before your procedure; if it is after 9:00 AM, take Dose 1 between 6 and 8 PM. Take Dose 2 4 hours before you leave home for your appointment. Follow each dose with 32 ounces of clear liquid.
Can I mix Plenvu ahead of time?
The practice’s instructions say Dose 1 may be mixed up to 6 hours before your prep start time if it is kept refrigerated. Stir or shake until the powder is completely dissolved, which can take 2 to 3 minutes.
What can I eat and drink before Plenvu?
Three days before your procedure, avoid raw fruits and vegetables, whole-wheat and multigrain products, beans, nuts, popcorn and seeds. The day before, have clear liquids only: water, coffee, tea, broth, sodas, apple juice, sports drinks, gelatin, popsicles and hard candy. No solid food, no milk, and nothing red or purple.
What if I feel sick while taking Plenvu?
Slow down your prep intake and walk around until the nausea settles, then continue. Baby wipes or a cleansing lotion can reduce irritation during the prep. If you vomit repeatedly or cannot finish the prep, call (346) 340-4414.
When do I have to stop eating and drinking?
Clear liquids are allowed until 3 hours before your appointment arrival time. From 3 hours before arrival, take absolutely nothing by mouth, including gum, hard candy and breath mints. Prescription medicines you have been told to take may be taken with water up to 3 hours before arrival.
I have diabetes or take a GLP-1 medicine. What changes?
Read the GLP-1 and diabetic prep sections on this page. Weekly GLP-1 medicines are held 7 days before the procedure and daily ones on the day of the procedure, as instructed. Do not take oral diabetes pills on prep day or procedure day, reduce insulin as described, and contact your diabetes doctor for instructions if you use an insulin pump.
United Gastroenterology Associates Offices
Questions about your prep or appointment can be answered by either office. Your arrival location and time are in your appointment instructions.
United Gastroenterology Associates – Katy
Katy Freeway (I-10) near the Grand Parkway
- Address: 23920 Katy Freeway, Suite 555, Katy, TX 77494
- Phone: (346) 340-4414
- Hours: Monday–Friday, 8:30 AM–5:00 PM (closed 12:00–1:30 PM for lunch; last appointment 4:30 PM)
United Gastroenterology Associates – Cypress
Northwest Freeway (US-290) in Cypress
- Address: 21216 Northwest Freeway, Suite 640, Cypress, TX 77429
- Phone: (346) 340-4414
- Hours: Monday–Friday, 8:30 AM–5:00 PM (closed 12:00–1:30 PM for lunch; last appointment 4:30 PM)
Ready to Start Your Plenvu Prep?
Read the General Colonoscopy Instructions first, follow the Plenvu steps above, and call (346) 340-4414 with any questions or difficulty during the prep.
Sources
- U.S. National Library of Medicine. DailyMed: Plenvu (PEG-3350, sodium ascorbate, sodium sulfate, ascorbic acid, sodium chloride and potassium chloride) prescribing information and medication guide. dailymed.nlm.nih.gov
- American Society for Gastrointestinal Endoscopy. Understanding Bowel Preparation. asge.org
These are the patient preparation instructions of United Gastroenterology Associates for Plenvu. They do not replace the personal instructions you receive from your doctor. Do not change any medicine without medical guidance. For a medical emergency, call 911. Last updated October 21, 2026.