Prior to bowel cleansing, a copy of the patient information (containing careful instructions on the proper methods of reconstitution and administration of the laxatives) provided by the manufacturer should be given to the patient.245,246,247,248,253
Reconstitution and Administration 
Glycerin solutions 239,242 and suppositories should be administered rectally.238,240,241,254,255 Polyethylene glycol 3350 electrolyte solutions are administered orally or through a nasogastric tube.244,245,246,247,248,253 Solutions of sorbitol (25-30%) usually are administered rectally.
Oral or Nasogastric Administration (Polyethylene glycol 3350, Polyethylene glycol 3350 with Electrolytes)
When polyethylene glycol is used for constipation, polyethylene glycol 3350 powder for oral solution (MiraLAX®) should be reconstituted with 120-240 mL of water (cold, room temperature, or hot).244
When polyethylene glycol is used for bowel cleansing, polyethylene glycol 3350 powder (with electrolytes) for oral or nasogastric solution should be reconstituted with the appropriate amount of lukewarm water as directed by the manufacturer.245,246,247,248,252,253 The solution should be shaken vigorously until the ingredients are dissolved; additional ingredients (e.g., flavorings other than those provided by the manufacturers) are not recommended.245,246,247,248,252,253
The reconstituted solutions should be refrigerated.245,246,247,248,252,253 Palatability of the oral solution may be increased if the reconstituted solution is chilled prior to administration;245,247 however, a chilled polyethylene glycol 3350 electrolyte solution is not recommended for infants.253
Administration of Polyethylene Glycol 3350 Electrolyte Solutions for Bowel Cleansing
Patients should fast for approximately 3 or 4 hours before administration of polyethylene glycol 3350 electrolyte solution.245,246,247,253 In addition, patients should be advised not to eat solid foods for at least 2 hours prior to administration of the drug.245,246,247,253 Polyethylene glycol 3350 electrolyte solutions are administered orally, but may be given through a nasogastric tube if patients are unwilling or unable to drink the solution.245,246,247 Rapid drinking of each polyethylene glycol 3350 electrolyte solution portion is preferred to drinking small amounts continuously.245,246,247,252,253
Polyethylene glycol 3350 electrolyte solutions may be given by single-dose regimens (usually on the evening prior to the colonoscopy [e.g., 6 p.m.]) or, if the procedure is scheduled for midmorning or later, patients should be allowed 3 hours for drinking the solution and 1 hour for complete bowel evacuation).245,248,251,261,262 Alternatively, a divided-dose regimen (usually consuming a portion on the evening prior to the colonoscopy and the remaining solution on the morning of the colonoscopy) may be used.248,251,261,262 Clinical studies suggest that the divided-dose polyethylene glycol 3350 electrolyte solution regimen (e.g., 2-3 L the evening before and 1 L the morning of the procedure) is superior to the standard single-dose regimen (e.g., 4 L administered on the evening prior to the procedure).251,261,262 In one study, polyethylene glycol 3350 electrolyte solution consumption less than 5 hours before colonoscopy was superior to a regimen administered 19 hours or more before the procedure.251,260 If a patient has an afternoon colonoscopy, a portion of the polyethylene glycol 3350 solution should be administered on the morning of the colonoscopy to improve bowel cleansing results.251,260
Administration Precautions for Polyethylene glycol 3350 Electrolyte Solutions
Polyethylene glycol 3350 electrolyte solutions should be used with caution in patients with impaired gag reflex, unconscious or semiconscious patients, and those prone to regurgitation or aspiration; these patients should be observed during administration, especially if the solution is administered through a nasogastric tube.245,246,247,248,252,253
If severe discomfort or distention occurs while consuming polyethylene glycol 3350 electrolyte solutions, administration of the drug should be slowed or temporarily discontinued until symptoms abate.245,246,248,252,253
Rectal Administration (Glycerin)
Regular glycerin suppositories should be moistened with lukewarm water before insertion high into the rectum.269 (See Dosage and Administration: Administration, in the Cathartics and Laxatives General Statement 56:12.) With steady pressure, the tip of the suppository should be inserted gently high into rectum.238,240,241,254,255 Patients should be instructed to retain the suppository for 15 minutes; melting of the suppository is not required to produce laxative action.238,240,241,254,255
Before administering glycerin laxative enemas, the patient should initially lie on the left side with the right knee bent and arms resting comfortably239,242 or should kneel on the bed with the head and chest lowered and forward until the left side of the face is resting on the surface of the bed.239,269 With steady pressure, the enema nozzle should be inserted into the rectum with side-to-side movement with the tip pointing toward navel until the entire dose is expelled.239,242,269 While squeezing the container, the tip should be removed from rectum and the unit discarded.239,242 Use of glycerin laxative enemas should be discontinued if resistance is encountered.239,242 Enema fluids, if properly introduced, usually provide adequate evacuation if retained until definite lower abdominal cramping is felt.269 (See Dosage and Administration: Administration, in the Cathartics and Laxatives General Statement 56:12.)
For the treatment of constipation, hyperosmotic laxatives should be administered only at infrequent intervals in single doses at the lowest effective dosage level, and usually for periods not exceeding 1 week; laxatives should be used for longer periods only under the management of a clinician and as part of a carefully planned therapeutic regimen.269 (See Dosage and Administration: Dosage, in the Cathartics and Laxatives General Statement 56:12.)
Only extremely high oral doses of sorbitol (25 g daily) or glycerin exert laxative action.269 (See Pharmacology: Hyperosmotic Laxatives, in the Cathartics and Laxatives General Statement 56:12.)
For the treatment of constipation, the usual rectal dose of glycerin for adults is 2-3 g as a suppository238,240 or 5.6-15.3 g (5-15 mL) as an enema.239 Children 2 to younger than 6 years of age may receive 1-1.2 g as a suppository240,241 or 2.3 g (2.3 mL) as an enema;242 children 6 years of age and older may be given 2-2.1 g as a suppository238,240 or 5.6 g (5.5 mL) as an enema.239
If a bowel movement does not occur after using the glycerin suppository or enema, the drug should be discontinued.239,241,242
For the treatment of constipation, the usual rectal dose of sorbitol as a 25-30% solution is (administered as enemas) 120 mL for adults and children 12 years of age and older or 30-60 mL for children 2-11 years of age.
When used as an adjunct to sodium polystyrene sulfonate resin, 15 mL of a 70% sorbitol solution may be administered orally until diarrhea occurs or 20-100 mL of the solution may be used as an oral vehicle for the resin. Alternatively, the resin may be given rectally as a 25% solution of sorbitol (see Sodium Polystyrene Sulfonate 40:18.18.)
For the treatment of constipation, the usual oral dosage in adults is 17 g (MiraLAX®) daily as needed for up to 7 days.244
Polyethylene Glycol 3350 (with Electrolytes)
To empty the bowel prior to colonoscopy or barium radiologic examination, children 6 months of age or older may receive orally or by nasogastric tube 25 mL/kg (2.6 g/kg) per hour (NuLYTELY®or Trilyte®) until watery stool is clear and free of solid matter (NuLYTELY®or Trilyte®) or 4 L is consumed (Trilyte®).246,253
To empty the bowel prior to colonoscopy or barium radiologic examination, the recommended dosage given by nasogastric tube in adults is 4 L administered at a rate of 20-30 mL (1.18-1.77 g [Golytely®]; 2.1-3.15 g [Nulytely®]; 1.2-1.8 g [Colyte®]) per minute (1.2-1.8 L/hour).245,246,247,251,259
To empty the bowel prior to colonoscopy or barium radiologic examination, adults may receive 240 mL (about 14 g [GoLYTELY®], 25 g [NuLYTELY®], about 14 g [Colyte®], 25 g [Trilyte®]) orally every 10 minutes until rectal output is clear or 4 L is consumed.245,246,247,253,259 Alternatively, adults may receive a single-dose regimen of 240 mL (24 g [MoviPrep®]) orally every 15 minutes until 1 L is consumed followed by drinking of an additional 1 L (for a total of 2 L of MoviPrep®) 1.5 hours later.248 An additional 1 L of clear liquid shoudl be ingested during the evening prior the procedure.248
When using a divided-dose regimen, adults may receive 240 mL (24 g [MoviPrep®]) every 15 minutes until 1 L is consumed followed by drinking an additional 0.5 L of clear liquid in the evening before the procedure,248 On the morning of the procedure, these adults should receive 240 mL (24 g [MoviPrep®]) every 15 minutes until 1 L is consumed followed by drinking an additional 0.5 L of clear liquid at least 1 hour prior to the procedure.248
Alternatively, adults may receive a combination regimen of polyethylene glycol 3350 electrolyte solution and bisacodyl (HalfLytely®). In this regimen, patients initially should receive 20 mg of bisacodyl (four 5-mg bisacodyl delayed-release tablets) and wait for a bowel movement or a maximum of 6 hours, then drink 240 mL of polyethylene glycol 3350 electrolyte solution every 10 minutes until a total of 2 L has been consumed.