Introduction ⬇
VA Class:GA201
ATC Class:A06AC06
AHFS Class:
- Cathartics and Laxatives 56:12
Generic Name(s):
Cellulose derivatives (methylcellulose), malt soup extract, and psyllium preparations are bulk-forming laxatives.
Dosage and Administration ⬆ ⬇
Administration 
Bulk-forming laxatives are administered orally. Commercially available powders, flakes, granules, tablets, and liquids should be dissolved and/or diluted according to the instructions of the manufacturer. In the treatment of constipation, at least one full glass (250 mL) of liquid should be administered with each laxative dose. When used to increase the bulk of stools in patients with chronic, watery diarrhea, one manufacturer suggests that one-third of a glass (80 mL) of liquid be administered with each dose.
Dosage
Bulk-forming laxatives are usually administered 1-3 times daily. To reduce the risk of esophageal obstruction in patients receiving large (e.g., the maximum daily dosage recommended by the manufacturer) dosages of bulk-forming laxatives, these laxatives should be administered in divided doses instead of a single daily dose.110 The usual dosages for the individual bulk-forming laxatives are below; for dosages in children younger than the ages listed, a physician should be consulted.
Methylcellulose
Adults and Children 12 and Older
The usual dosage is up to 6 g daily given in divided doses of 0.45-3 g per dose.
Children 6-11 Years of Age
The usual dosage is up to 3 g daily given in divided doses of 0.45-1.5 g per dose.
Malt Soup Extract
Adults and Children 12 and Older
The usual dosage is up to 64 g daily given in divided doses of 3-32 g per dose.
Children 6-11 Years of Age
The usual dosage is up to 32 g daily given in divided doses of 3-16 g per dose.
Children 2-5 Years of Age
The usual dosage is up to 16 g daily given in divided doses of 3-8 g per dose.
Psyllium Preparations
Adults and Children 12 and Older
The usual dosage is up to 30 g daily given in divided doses of 2.5-7.5 g per dose.
Children 6-11 Years of Age
The usual dosage is up to 15 g daily given in divided doses of 2.5-3.75 g per dose.
Constipation and pain from diverticular disease appear to respond to daily doses of about 18 g of dietary bran.
Cautions ⬆ ⬇
Precautions and Contraindications
Potentially severe hypersensitivity reactions, including rhinoconjunctivitis, acute bronchospasm, and anaphylaxis, can occur in susceptible individuals (e.g., those with psyllium sensitivity or suffering from respiratory disorders) following inhalation of psyllium dust particles.106 Therefore, inhalation of psyllium hydrophilic mucilloid particles should be avoided.106 To minimize exposure and, therefore, sensitization to airborne particles of psyllium, one manufacturer suggests that health-care personnel dispense powdered psyllium preparations with a spoon rather than pouring them directly from the container into the glass for administration.111 In some cases, resassignment of health-care personnel to areas (e.g., non-geriatric units) where use of bulk powder formulations of psyllium was minimal has been necessary.106
Individuals with phenylketonuria (i.e., homozygous genetic deficiency of phenylalanine hydroxylase) and other individuals who must restrict their intake of phenylalanine should be warned that each 3.4-g dose of psyllium hydrophilic mucilloid given as Metamucil® Smooth Texture Sugar Free Orange Flavor contains aspartame (NutraSweet®) which is metabolized in the GI tract to provide about 25 mg of phenylalanine following oral administration.100,101,102,103,104,105
For a complete discussion of the precautions associated with bulk-forming laxatives, see Cautions in the Cathartics and Laxatives General Statement 56:12.
Other Information ⬆ ⬇
Pharmacokinetics
Bulk-forming laxatives generally are not absorbed from the GI tract. However, malt soup extract has been reported to be hydrolyzed in the colon, absorbed, and then metabolized by the liver. A laxative effect of the bulk-forming laxatives is usually apparent within 12-24 hours, but the full effect may not be apparent for 2-3 days.
Chemistry
Cellulose derivatives (methylcellulose), malt soup extract, and psyllium preparations are bulk-forming laxatives.
Methylcellulose
Methylcellulose occurs as a white, fibrous powder or granules. When mixed with water, methylcellulose produces clear to opalescent viscous colloidal suspensions; the drug is insoluble in alcohol.
Malt Soup Extract
Malt soup extract is obtained from the grain of one or more varieties of barley and contains 73% maltose, 12% other polymeric carbohydrates, 7% protein, and 1.5% potassium in addition to small amounts of calcium, phosphorus, magnesium, and vitamins. The drug swells in water.
Psyllium Preparations
Psyllium preparations are obtained from the seeds of a variety of species of Plantago. Plantago or psyllium seed is the cleaned, dried, ripe seed of Plantago psyllium and related species. The coating of the dried, ripe Plantago seed has a high content of hemicellulose mucillages; psyllium hydrophilic mucilloid, obtained from the coating of Plantago ovata, contains about 50% hemicellulose.
Additional Information
For further information on pharmacology, uses, cautions, drug interactions, and dosage and administration of the bulk-forming laxatives, see the Cathartics and Laxatives General Statement 56:12.
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.
Malt Soup Extract
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|
Oral | Powder | 1 g/g | Maltsupex® | Wallace |
| Solution | 5.3 g/5 mL | Maltsupex® | Wallace |
| Tablets | 750 mg | Maltsupex® | Wallace |
Malt Soup Extract Combinations
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|
Oral | Powder | 500 mg/g with Psyllium Hydrophilic Mucilloid 500 mg/g | Syllamalt® | Wallace |
Methylcellulose
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|
Bulk | Powder* | | | |
Oral | Powder | 105 mg/g | Citrucel® | GlaxoSmithKline |
| | 196 mg/g | Citrucel® | GlaxoSmithKline |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Psyllium Hydrophilic Mucilloid
Psyllium Hydrophilic Mucilloid Combinations
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|
Oral | Powder | 542 mg/g with Sennosides 123 mg/g | Perdiem® Overnight Relief | Novartis |
Copyright ⬆ ⬇
AHFS® Drug Information. © Copyright, 1959-2024, Selected Revisions January 1, 2009. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, MD 20814.
References ⬆
Only references cited for selected revisions after 1984 are available electronically.
100. Procter & Gamble. Metamucil® Fiber Laxative (psyllium husk) prescribing information. In: Physicians' desk reference. 55th ed. Montvale, NJ: Medical Economics Company Inc; 2001:2662-3.
101. American Medical Association Council on Scientific Affairs. Aspartame: review of safety issues. JAMA . 1985; 254:400-2. [PubMed 2861297]
102. Gossel TA. A review of aspartame: characteristics, safety and uses. US Pharm . 1984; 9:26,28-30.
103. Food and Drug Administration. Aspartame as an inactive ingredient in human drug products; labeling requirements. Proposed rule. [21 CFR Part 201] Fed Regist . 1983; 48:54993-5. (IDIS 178728)
104. Food and Drug Administration. Food additives permitted for direct addition to food for human consumption; aspartame. Final rule. [21 CFR Part 172] Fed Regist . 1983; 48:31376-82. (IDIS 172957)
105. Anon. Aspartame and other sweeteners. Med Lett Drugs Ther . 1982; 24:1-2. [PubMed 7054648]
106. Schoenwetter WF, Steinberg P. Psyllium hypersensitivity, nurses, and geriatric units. Ann Intern Med . 1985; 103:642. [PubMed 4037572]
108. Bell LP, Hectorne K, Reynolds H et al. Cholesterol-lowering effects of psyllium hydrophilic mucilloid: adjunct therapy to a prudent diet for patients with mild to moderate hypercholesterolemia. JAMA . 1989; 261:3419-23. [PubMed 2724486]
109. Anderson JW, Zettwoch N, Feldman T et al. Cholesterol-lowering effects of psyllium hydrophilic mucilloid for hypercholesterolemic men. Arch Intern Med . 1988; 148:292-6. [PubMed 3277558]
110. Food and Drug Administration. Warning statements required for over-the-counter drugs containing water-soluble gums as active ingredients: proposed rule. (21 CFR Part 201). Fed Regist . 1990; 45782-5.
111. Procter & Gamble Company, Cincinnati, OH: Personal Communication.