Bulk-Forming Laxatives

Name: Bulk-Forming Laxatives

Introduction

Cellulose derivatives (methylcellulose), calcium polycarbophil, malt soup extract, and psyllium preparations are bulk-forming laxatives.a b f

Uses for Bulk-Forming Laxatives

Constipation

Relief of occasional constipation; restore bowel movement regularity.e f g h i j k l

Initial treatment of choice for simple constipation caused by a low-fiber and/or low-fluid diet.b

Bulk-forming laxatives, stool softeners, or mineral oil preferred in conditions in which straining at defecation should be avoided (e.g., MI, vascular diseases, diseases of the anus or rectum, hernias, recent rectal surgery).b

Treatment of constipation that occurs following prolonged bed rest or hospitalization.b i

Treatment of choice for constipation resulting from diminished colonic motor response in geriatric patients;b i condition is usually due to psychological or physical laxative dependence.b

Bulk-forming laxatives or stool softeners are the preferred treatment for constipation occurring during pregnancy or the puerperium.b i

Not for use when prompt or thorough bowel evacuation is necessary (e.g., poisonings, radiologic examination, bowel surgery).b

Diarrhea

Increase the bulk of stools in patients with chronic, watery diarrhea; subjective improvement noted but the total water content of the stool was unchanged.b

GI Pain

Reduce intraluminal rectosigmoid pressure and pain in diverticular disease.b i

Hypercholesterolemia†

Psyllium preparations have been used as an adjunct to dietary therapy to reduce elevated serum total cholesterol, LDL cholesterol, apolipoprotein B (apo B) concentrations and the ratio of LDL-cholesterol to HDL-cholesterol in adults with mild to moderate hypercholesterolemia†.108 109

Bulk-Forming Laxatives Dosage and Administration

Administration

Oral Administration

Administer orally, in conjunction with adequate fluid intake.a b c d e f g h i j l

For treatment of constipation, administer ≥1 full glass (250 mL) of liquid with each dose.110 a c d e f g h i j k l Some manufacturers recommend another full glass of liquid after dose.e l

When used to increase the bulk of stools in chronic, watery diarrhea, one manufacturer suggests administering 1/3 of a glass (80 mL) of liquid with each dose.a

Administer as infrequently as possible at the lowest effective dosage level.b Do not use for >1 week unless directed by a clinician.b d e f g h i j k

In patients receiving large dosages, administer in divided doses instead of a single daily dose to reduce the risk of esophageal obstruction.110

To minimize side effects, initially administer 0.5–1 dose daily; increase as needed up to 3 doses daily.d i j l

Methylcellulose Powder

Fill glass with ≥240 mL (8 ounces) of cold water; level powder and add to water; stir briskly and drink promptly.e h Chocolate powder may be mixed with milk.h

Psyllium Powder

Place dose in empty glass; fill with ≥240 mL of water or other beverage; stir briskly and drink promptly.i j k l If mixture thickens, add additional liquid and stir.i j l

Psyllium Capsule

Swallow 1 capsule at a time.c i

Dosage

Available as calcium polycarbophil; dosage expressed in terms of polycarbophil.f

Pediatric Patients

Constipation Oral (Calcium Polycarbophil Caplet)

Children ≥12 years of age: Initially, 1 g once daily.f May increase gradually as needed up to 4 times daily.f

Oral (Methylcellulose Caplet)

Children 6–12 years of age: 500 mg (1 caplet) 1–6 times daily.g

Children >12 years of age: 1 g (2 caplets) 1–6 times daily.g

Oral (Methylcellulose Powder)

Children 6–11 years of age: 1 g 1–3 times daily.e h

Children ≥12 years of age: 2 g 1–3 times daily.e h

Oral (Malt Soup Extract)

Children 2–5 years of age: 3–8 g 1–3 times daily.a

Children 6–11 years of age: 3–16 g 1–3 times daily.a

Children ≥12 years of age: 3–32 g 1–3 times daily.a

Oral (Psyllium Capsule)

Children ≥12 years of age: 2.6 g (5 capsules) 1–3 times daily.c i

Oral (Psyllium Powder)

Children 6–11 years of age: Usually, 1.7 g 1–3 times daily.i j

Children 6–11 years of age (Hydrocil): 3.5 g; maximum 14 g daily in divided doses.k

Children 6–11 years of age (Konsyl): 3 g 1–3 times daily.l

Children ≥12 years of age: Usually, 3.4 g 1–3 times daily.i j

Children ≥12 years of age (Hydrocil): 3.5–7 g; maximum 28 g daily in divided doses.k

Children ≥12 years of age (Konsyl): 6 g 1–3 times daily.l

Oral (Psyllium Wafer)

Children 6–11 years of age: 1.7 g (1 wafer) 1–3 times daily.d i

Children ≥12 years of age: 3.4 g (2 wafers) 1–3 times daily.d i

Adults

Constipation Oral (Calcium Polycarbophil Caplet)

1 g once daily.f May increase gradually as needed up to 4 times daily.f

Oral (Methylcellulose Caplet)

1 g (2 caplets) 1–6 times daily.g

Oral (Methylcellulose Powder)

2 g 1–3 times daily.e h

Oral (Malt Soup Extract)

3–32 g 1–3 times daily.a

Oral (Psyllium Capsule)

2.6 g (5 capsules) 1–3 times daily.c i

Oral (Psyllium Powder)

Usually, 3.4 g 1–3 times daily.i j

Hydrocil: 3.5–7 g; maximum 28 g daily in divided doses.k

Konsyl: 6 g 1–3 times daily.l

Oral (Psyllium Wafer)

3.4 g (2 wafers) 1–3 times daily.d i

Hypercholesterolemia† Oral (Psyllium Capsule)

3.2 g (6 capsules) 3 times daily.c

Oral (Sugar-Free Psyllium Powder)

3.4 g 3 times daily before meals.108 109

Prescribing Limits

Pediatric Patients

Constipation Oral (Calcium Polycarbophil Caplet)

Children ≥12 years of age, as self-medication: Maximum 4 g (8 caplets) daily; maximum of 7 days.f

Oral (Malt Soup Extract)

Children 2–5 years of age: Maximum 16 g daily.a

Children 6–11 years of age: Maximum 32 g daily.a

Children ≥12 years of age: Maximum 64 g daily.a

Oral (Psyllium Powder)

Children 6–11 years of age (Hydrocil): Maximum 14 g daily.k

Children ≥12 years of age (Hydrocil): Maximum 28 g daily.k

Adults

Constipation Oral (Calcium Polycarbophil Caplet)

Self-medication: Maximum 4 g (8 caplets) daily; maximum of 7 days.f

Oral (Malt Soup Extract)

Maximum 64 g daily.a

Oral (Psyllium Powder)

Hydrocil: Maximum 28 g daily.k

Special Populations

No special population dosage recommendations at this time.c d e f i j k l

Bulk-Forming Laxatives Pharmacokinetics

Absorption

Bioavailability

Generally not absorbed following oral administration.a Malt soup extract reported to be hydrolyzed and absorbed in the colon.a

Onset

Following oral administration, laxative effect usually occurs within 12–72 hours; full effect may not be apparent for 2–3 days.a c d e f g h i j k l

Elimination

Metabolism

Malt soup extract reportedly metabolized in the liver.a

Advice to Patients

  • Importance of informing clinicians before use if abdominal pain, nausea, or vomiting is present or of a sudden change in bowel habits that persists over a period of 2 weeks.b c d e f g h i j k l

  • Importance of adequate fluid intake (e.g., ≥250 mL) with each dose to minimize the risk of choking or asphyxiation.c d e f g h i j k l

  • Importance of informing patients with phenylketonuria that Citrucel Sugar Free Orange Flavor, Metamucil Smooth Texture Sugar Free Orange Flavor and Berry Flavor, and Citrucel Fiber Shake, Chocolate Flavor, contain aspartame.e h i j

  • Advise patients sensitive to milk that Citrucel Fiber Shake, Chocolate Flavor, contains dry milk powder.h

  • Importance of not using laxative products for >1 week unless directed by a clinician.b c d e f g h i j k

  • Importance of stopping use and informing a clinician if a bowel movement does not occur or rectal bleeding occurs after use. c d e f g h i j k l

  • Inform patients of symptoms of esophageal obstruction (e.g., chest pain and/or pressure, regurgitation, vomiting, difficulty in swallowing and/or breathing); advise patients to immediately contact their clinician if such symptoms occur.110 c d e f g h i j k l

  • Advise patients to take calcium polycarbophil and psyllium laxatives ≥2 hours before or 2 hours after other oral medicines.c d f i j l

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs.

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.a

  • Importance of informing patients of other important precautionary information. (See Cautions.)

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