Bowel Preparation

1. Indications
   1. Colonoscopy
   2. Flexible Sigmoidoscopy
2. Protocol: General
   1. Evening-Morning Protocol
      1. Split dosing with half of preparation in evening and other half in morning, 4-6 hours before procedure
      2. Now preferred as Bowel Preparation
   2. Sedated procedure preparation
      1. No solids for >6 hours before procedure
      2. No liquids for >2 hours before procedure
   3. Bloating or Nausea
      1. Remain ambulatory as this may reduce symptoms
      2. Wait longer between doses
   4. Medications
      1. Take with sip of water up to 3-4 hours before the procedure
      2. Stop NSAIDs, iron supplement, fish oil up to 1 week prior to procedure
      3. Low dose Aspirin can typically be continued (although does increase risk of bleeding from biopsy sites)
      4. Diabetic medications
         1. Prep Day (evening prior to procedure)
            1. Consider decreasing Bolus Insulin (e.g. InsulinLispro) and Sulfonylureas (e.g. Glipizide) to half dose
         2. Procedure Day
            1. Consider decreasing basal Insulin dose (e.g. Lantus, Levemir) to half dose
3. Protocol: First-Line agents
   1. Clear Liquid Diet on the evening before procedure
      1. Do not use any red or purple colored flavorings or liquids
   2. Protocol 1: PEG Solution such as Golytely (4 Liters)
      1. May have seawater or sulfur taste
      2. Consider chilling, drinking with straw and adding citrus flavor crystal light (or lemon juice) for better taste
      3. Consider sulfate-free PEG (NuLytely, TriLyte) for better taste at reasonable cost ($20)
   3. Protocol 2: PEG Solution with half the volume (2 Liters)
      1. Low volume prep: HalfLytely, Moviprep, Plenvu (expensive, $120)
         1. Administer 2 Liters of the concentrated solution
      2. Low Volume non-PEG solutions: Suprep, Clenpiq
         1. Administer 2 Liters of the concentrated solution
         2. Risk of osmotic Electrolyte shifts and Acute Kidney Injury (esp. if use of NSAIDs, ACE Inhibitors)
      3. Alternative (low volume at generic cost)
         1. First: Bisacodyl 10-20 mg orally
         2. Next (2 hours later): 2 Liters of standard PEG Solution (e.g. Golytely or NuLytely)
   4. Protocol 3: Tablets with fluid
      1. Sutab 24 tablets taken with 3 Liters of fluid ($150)
      2. Osmoprep 32 tablets taken with 2 Liters of fluid ($250)
   5. Protocol 4: Miralax (better taste)
      1. First: Bisacodyl 10-20 mg orally
      2. Next
         1. Combine Miralax (PEG 3350) and Gatorade (or similar)
            1. Miralax 238 gram bottle and
            2. Light colored Gatorade or similar liquid 64 ounces
         2. Drink 8 ounces of the Miralax-Gatorade every 10 minutes
         3. Risk of greater Electrolyte losses than with prescription PEG solutions
4. Protocol: Prepopik (Stimulant Laxative with Magnesium Citrate)
   1. Contraindications (use PEG option instead)
      1. Renal disease with Electrolyte abnormalities
      2. Congestive Heart Failure
      3. Advanced age
   2. Preparation
      1. Mix one packet with 5 oz water immediately before dose
   3. Morning procedure
      1. First
         1. Take dose 1 on the afternoon of the day before the procedure
         2. Follow with five 8-ounce glasses of water (40 oz)
      2. Next
         1. Take dose 2 at six hours after the first dose
         2. Follow with three 8-ounce glasses of water (24 oz)
   4. Afternoon procedure
      1. First
         1. Take dose 1 on the evening of the day before the procedure
         2. Follow with five 8-ounce glasses of water (40 oz)
      2. Next
         1. Take dose 2 at five hours before the procedure
         2. Follow with three 8-ounce glasses of water (24 oz)
   5. References
      1. (2012) Presc Lett 19(11):66
5. Protocol: Other
   1. Precautions
      1. These protocols have fallen into disuse due to concerns about efficacy and safety
      2. Risk of Hypermagnesemia in elderly
   2. Protocol 1: Two Laxatives on evening before procedure
      1. Bisacodyl (Dulcolax) take four 5 mg tablets
      2. Magnesium Citrate take 290 ml bottle
6. Protocol: Older listed for historical reasons (avoid due to nephrotoxicity)
   1. Protocol 1: Combined Laxative and fleets
      1. Laxatives on evening before procedure
         1. Bisacodyl (Dulcolax) take four 5 mg tablets
      2. Enemas on morning of procedure
         1. First Fleets Enema 1.5 hours before procedure
         2. Second Fleets Enema 0.5 hours before procedure
         3. Third Fleets Enema if second enema fluid not clear
   2. Protocol 2: Fleet Phospho-Soda
      1. Fleet Phospho-Soda is one of the most effective and well tolerated preparations
      2. However, not recommended due to renal Calcium precipitation and Renal Injury risk
7. References
   1. (2014) Presc Lett 21(3)
   2. (2021) Presc Lett 28(4): 22-3
   3. Sin Sil Park (2012) Am J Gastroenterol 105: 1319-26 [PubMed]
   4. Marmo (2010) Gastrointest Endosc 72:313-20 [PubMed]