Bulk-Forming Laxatives (Monograph)

Brand names: Citrucel, Fibercon, Hydrocil, Konsyl, Metamucil
Drug class: Cathartics and Laxatives
ATC class: A06AC06
VA class: GA201
CAS number: 9004-67-5

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† [off-label]

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^{† [off-label]}.^{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.^{m o p 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† [off-label]

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}

Cautions for Bulk-Forming Laxatives

Contraindications

• Known hypersensitivity to bulk-forming laxatives or any ingredient in the formulation.^{c d}

• Acute abdominal pain, nausea, vomiting, or other symptoms of appendicitis or undiagnosed abdominal pain.^{b c d e f g i j k l}

• Partial obstruction of the bowel.^b

• Esophageal obstruction, dysphagia, or problems of the throat.^{110 o p b c d e f g i j k l} (See Obstruction under Cautions.)

• Sudden change in bowel habits that lasts >2 weeks.^{c d e f g i j k l}

Warnings/Precautions

Warnings

Obstruction

Bowel and/or esophageal obstruction, swelling or blockage of the throat, choking, or asphyxiation reported when insufficient liquid (e.g., <250 mL) administered with some bulk-forming laxatives.^{m n o p q r s 110 c d e f g h i j k l} Administer each dose with ≥1 full glass (250 mL) of liquid.^{m 110 o p c d e f g h i j k l} (See Administration under Dosage and Administration and also see Contraindications under Cautions.)

Sensitivity Reactions

Psyllium Hypersensitivity

Serious hypersensitivity reactions possible to inhaled or ingested psyllium.^{a c d i j l}

Do not inhale psyllium hydrophilic mucilloid particles.¹⁰⁶ Severe hypersensitivity reactions (e.g., rhinoconjunctivitis, acute bronchospasm, anaphylaxis) may occur in susceptible individuals (e.g., those with psyllium sensitivity or suffering from respiratory disorders) following inhalation of psyllium dust particles.^{106 t}

One manufacturer suggests that health-care personnel dispense powdered psyllium preparations with a spoon instead of pouring them directly from the container to minimize exposure and sensitization to airborne particles of psyllium.^{111 i}

Milk Hypersensitivity

Citrucel Fiber Shake, Chocolate Flavor, contains dry milk powder; hypersensitivity reactions possible in patients sensitive to milk.^h

Phenylketonuria

Metamucil Smooth Texture Sugar Free Orange Flavor contains aspartame (NutraSweet), which is metabolized in the GI tract to provide 25 mg phenylalanine per 3.4 g dose.^{100 101 102 103 104 105 i}

Metamucil Sugar Free Berry Burst Flavor contains aspartame (NutraSweet), which is metabolized in the GI tract to provide16 mg phenylalanine per 3.4 g dose.^{101 102 103 104 105 j}

Citrucel Sugar Free Orange Flavor contains aspartame (NutraSweet), which is metabolized in the GI tract to provide 52 mg per 10.2 g dose. ^{101 102 103 104 105 e}

Citrucel Fiber Shake, Chocolate Flavor contains aspartame (NutraSweet), which is metabolized in the GI tract to provide 49 mg per 10.7 g dose. ^{101 102 103 104 105 h}

Specific Populations

Pregnancy

Psyllium: Category B.ⁱ

Pediatric Use

Safety and efficacy of methylcellulose not established in children <6 years of age.^{e g h}

Safety and efficacy of malt soup extract not established in children <2 years of age.^a

Safety and efficacy of psyllium powders and wafers not established in children <6 years of age.^{d i j k l}

Safety and efficacy of calcium polycarbophil and psyllium capsules not established in children <12 years of age.^{c f i}

Avoid use of laxatives in infants and children.^b

Renal Impairment

Use with caution and monitor electrolytes (e.g., magnesium, potassium) in patients with impaired renal function.^b

Common Adverse Effects

Psyllium: Changes in bowel habits, minor bloating.^{c d i j l}

Drug Interactions

GI Absorption of Other Drugs

By increasing intestinal motility, can potentially decrease transit time of concomitantly administered oral drugs and thereby decrease their absorption.^b

Administer ≥2–3 hours before or after other medications.^{b c d f i j l}

Specific Drugs

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

Stability

Storage

Oral

Calcium Polycarbophil Caplets

20–25°C; protect from moisture.^f

Methylcellulose Caplets

Tightly containers at 15–30°C; protect from moisture.^g

Methylcellulose Powder

Tight containers at <25°C; protect from humidity.^h

Psyllium Capsules

Tight containers at room temperature; protect from humidity.^c

Psyllium Wafer

Room temperature.^d

Actions

• Malt soup extract obtained from the grain of one or more varieties of barley.^a

• Plantago or psyllium seed is the cleaned, dried, ripe seed of Plantago psylliumand related species; the coating has a high hemicellulose mucilage content.^a

• Dissolves or swells in water to form an emollient gel or viscous (bulk) solution.^{b i} The resulting bulk causes enlargement of lumen of the colon and a softer stool, thereby decreasing intraluminal pressure and straining.ⁱ Promotes peristalsis and reduces transit time.^{b i}

• Reduces fecal pH and serum cholesterol, and alters the composition of fecal bile acids; may contribute to laxative effect.^b

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 o p 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.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Medical Disclaimer