Colonoscopy Bowel Prep (Klean-Prep, Moviprep, Plenvu)
The drinkable cleansing solutions taken the day before colonoscopy. Split-dose (half evening, half morning) gives the best results — and a clear colon means a thorough exam and accurate findings.
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
Drug class
Bowel cleansing solutions (osmotic laxatives at high volume)
Examples
**High-volume PEG-electrolyte**: Klean-Prep, GoLYTELY (4 L total — older standard). **Lower-volume PEG with ascorbic acid**: Moviprep (2 L), Plenvu (1 L). **Sodium picosulphate-magnesium citrate**: Picolax, CitraFleet — small volume, sweeter taste. **Sodium phosphate (less used now)**: associated with kidney injury risk.
How it works
PEG-electrolyte solutions are non-absorbable — they pull water into the bowel by osmosis and flush everything out. Adding ascorbic acid in newer formulations boosts the cleansing effect at smaller volumes. Sodium picosulphate works as a stimulant + osmotic combination at small volume.
What it treats
- Cleansing the colon for colonoscopy
- Cleansing for capsule endoscopy or barium enema
- Pre-surgical bowel preparation in some cases
How to take it
Day before colonoscopy: clear-liquid diet only (water, clear apple juice, broth, qahwa or tea without milk, jelly).
Split-dose (RECOMMENDED): half the prep solution starting around 6 PM evening before; second half starting 5-6 hours BEFORE your procedure (usually early morning of the procedure).
Drinking technique: drink one 250 mL glass every 15 minutes. Refrigerate it (better taste). Add ginger or lime to mask flavor. Use a straw past the back of the tongue.
Don't drink anything other than clear liquids during the prep.
Common side effects
- Nausea (very common)
- Bloating, cramping during prep
- Vomiting (try slower drinking)
- Anal soreness from frequent stools (use moisturizing wipes)
- Sleep disruption from waking to drink/use bathroom
- Hunger from clear-liquid diet
Serious side effects — call your doctor
Severe abdominal pain or vomiting that won't stop
Stop drinking; contact your endoscopy unit.
Symptoms of dehydration: severe dizziness, no urine, fainting
Drink clear liquids; if severe, ED.
Severe headache, irregular heartbeat (rare with newer preps)
Possible electrolyte imbalance — emergency.
Interactions
Hold these medications during prep: oral diabetes drugs (hypoglycemia risk), insulin (dose-adjust), iron tablets (color the colon), warfarin (per cardiologist), strong diuretics (dehydration risk). Take essential morning meds with a small sip of water on the day.
Prep can wash through other medications — take important meds at least 2 hours before starting prep.
Monitoring
No routine monitoring. Patients with kidney disease, heart failure, or elderly need individualized prep — discuss with your booking team.
When and how to stop
Complete the full prep — stopping early means inadequate cleansing and the colonoscopy will need to be repeated. Stop only for severe vomiting that won't stop, severe abdominal pain, or signs of allergic reaction.
Pregnancy & breastfeeding
Bowel prep should be avoided in pregnancy unless colonoscopy is essential. PEG-based preps preferred if needed.
In the Saudi context
All major preps available in Saudi Arabia. Lower-volume options (Moviprep, Plenvu) increasingly preferred for tolerability. MOH and insurance cover prep agents prescribed for screening or diagnostic colonoscopy.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- Will split-dose really make a difference?
- What if I throw up during the prep?
- Can I take my morning diabetes/blood pressure meds?
- Which medications should I stop, and when?
Medically reviewed by: SGA Patient Education Panel · Last reviewed 24/04/2026