Methylcellulose is a synthetic, orally administered, bulk-forming laxative used in the treatment of constipation and diarrhea. Methylcellulose is indicated for constipation that occurs in elderly patients as well as in patients with low-fiber diets, prolonged bed rest or hospitalization, pregnancy, colostomies, irritable bowel syndrome, or diverticular disease. It is also indicated for control of diarrhea in patients with chronic watery diarrhea. The drug is commonly used in children aged 6 years and older. Methylcellulose was originally approved by the FDA in 1942.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
-While not routinely recommended for methylcellulose, some experts advise that administration of bulk fiber laxatives be separated from administration of other oral drugs by at least 1-2 hours.
-All dosage forms: Take dosage with the appropriate amount of liquid to reduce risk of choking. Drinking another glass of water after consumption of the dose is also advised.
Oral Solid Formulations:
-Caplets: Administer each adult or children's dose with a full glass (8 ounces) of liquid.
Oral Liquid Formulations:
-Powder for oral solution: Mix the proper dose of powder in at least a full glass (8 ounces) of cold water prior to administration.
Troublesome adverse effects associated with methylcellulose are relatively uncommon and include abdominal pain or cramps, diarrhea, increased flatulence, nausea, and vomiting. Discontinue use if abdominal pain or vomiting occurs. Rarely, esophageal or GI obstruction, swelling of the throat, choking, or asphyxia can occur if insufficient liquid is administered with the drug. One full glass of liquid should be taken with each dose of the drug. Patients should be aware of the signs of esophageal obstruction and should notify their physician immediately if they experience chest pain (unspecified), regurgitation, vomiting, or difficulty swallowing or breathing.
Bulk-forming laxatives, such as methylcellulose, are contraindicated in patients with symptoms of acute abdomen or appendicitis, esophageal stricture or perforation, dysphagia, GI obstruction or ileus, or unexplained/undiagnosed abdominal pain. Do not use bulk-forming laxatives if nausea or vomiting are present. Patients should be advised to discontinue use and to consult their health care professional if they have noticed a sudden change in bowel habits that persists for two weeks, or if rectal GI bleeding or failure to produce a bowel movement occurs after the use of this laxative. For self-treatment, patients should not use this product for a period >= 1 week without provider consultation.
Patients with phenylketonuria should avoid the sugar-free preparations of methylcellulose; these contain aspartame, a compound that is metabolized in the GI tract to phenylalanine.
Methylcellulose is generally considered safe and effective for use as directed during pregnancy, though a specific pregnancy category is not assigned. The systemic absorption of methylcellulose is minimal; when used as directed, its use in pregnancy is generally considered to be safe and effective for the purpose of treating occasional constipation. Fiber supplements along with adequate fluid intake are often first line therapies for constipation during pregnancy. To avoid impaction, the drug should be taken with plenty of fluids as directed. Pregnant patients should generally consult with their healthcare provider prior to taking any fiber supplement.
Methylcellulose use during breast-feeding is considered compatible. Because the drug is not absorbed systemically by the mother, there is a lack of worry about excretion in breast milk. Adequate fluid intake and adequate fiber supplementation in the diet are first-line therapies for constipation during lactation. Adequate fluid intake is especially important to avoid impaction and straining following childbirth. Alternative fiber choices often recommended include psyllium.
The federal Omnibus Budget Reconciliation Act (OBRA) regulates the use of medications in residents (e.g., geriatric adults) of long-term care facilities. The OBRA guidelines caution that bulk forming laxatives, such as oral forms or methylcellulose, may cause accumulation of stool and possible bowel obstruction if not used with a sufficient amount of fluid or in patients with other causes of impaired bowel motility.
For treatment and prevention of constipation, as an adjunct for the management of irritable bowel syndrome* or diverticulosis*, or to aid in the management of chronic diarrhea*:
Oral dosage (regular Citrucel powder):
Adults and Adolescents: 1 heaping tablespoonful (2 g methylcellulose per 19 g powder) in at least 240 ml (8 oz) of water PO, given 1-3 times per day as needed.
Children 6-12 years: One-half tablespoonful (about 1 g methylcellulose per 9.5 g powder) in at least 240 ml (8 oz) of water PO, given once daily as needed.
Children < 6 years: Safety and efficacy have not been established.
Oral dosage (sugar-free Citrucel powder):
Adults and Adolescents: 1 rounded tablespoonful (2 g methylcellulose per 10.2 g sugar-free powder) in at least 240 ml (8 oz) of water PO, given 1-3 times per day as needed.
Children 6-12 years: One-half rounded tablespoonful (roughly 1 g methylcellulose per 5.1 g sugar-free powder) in at least 240 ml (8 oz) of water PO, given once daily as needed.
Children < 6 years: Safety and efficacy not been established.
Oral dosage (Citrucel fiber caplets):
Adults and Adolescents: 2 caplets (total 1 g methylcellulose) PO with at least 240 ml (8 oz) of liquid, up to 6 times per day as needed.
Children 6-12 years: 1 caplet (total 500 mg methylcellulose) PO with at least 240 ml (8 oz) of liquid, up to 6 times per day as needed.
Children < 6 years: Safety and efficacy have not been established.
Maximum Dosage Limits:
-Adults
3 tablespoons/day powder or 12 caplets/day PO with liquid.
-Elderly
3 tablespoons/day powder or 12 caplets/day PO with liquid.
-Adolescents
3 tablespoons/day powder or 12 caplets/day PO with liquid.
-Children
>= 6 years: One-half tablespoon/day powder or 6 caplets/day PO with liquid.
< 6 years: Maximum dosage information not available.
-Infants
Do not use (choking hazard).
Patients with Hepatic Impairment Dosing
It appears that no dosage adjustments are needed.
Patients with Renal Impairment Dosing
It appears that no dosage adjustments are needed.
*non-FDA-approved indication
Atropine; Difenoxin: (Moderate) Diphenoxylate can decrease GI motility. Drugs used to treat constipation, such as laxatives, would counteract the effect of antidiarrheals. In general, it would be illogical to concurrently administer these drugs at the same time. If an antidiarrheal medication is needed, it would be wise to temporarily discontinue use of agents with laxative effects.
Bumetanide: (Moderate) Loop diuretics may increase the risk of hypokalemia especially in patients receiving prolonged therapy with laxatives. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy.
Calcium Phosphate, Supersaturated: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery.
Dichlorphenamide: (Moderate) Use dichlorphenamide and methylcellulose together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
Diphenoxylate; Atropine: (Moderate) Diphenoxylate can decrease GI motility. Drugs used to treat constipation, such as laxatives, would counteract the effect of antidiarrheals. In general, it would be illogical to concurrently administer these drugs at the same time. If an antidiarrheal medication is needed, it would be wise to temporarily discontinue use of agents with laxative effects.
Ethacrynic Acid: (Moderate) Loop diuretics may increase the risk of hypokalemia especially in patients receiving prolonged therapy with laxatives. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy.
Furosemide: (Moderate) Loop diuretics may increase the risk of hypokalemia especially in patients receiving prolonged therapy with laxatives. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy.
Lactulose: (Major) In general, other laxatives, such as methylcellulose, should not be used concurrently with lactulose, especially during the initial phase of therapy for portal-systemic encephalopathy, because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved.
Loop diuretics: (Moderate) Loop diuretics may increase the risk of hypokalemia especially in patients receiving prolonged therapy with laxatives. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy.
Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery.
Torsemide: (Moderate) Loop diuretics may increase the risk of hypokalemia especially in patients receiving prolonged therapy with laxatives. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy.
Methylcellulose and other bulk-forming laxatives act by absorbing liquid in the gastrointestinal (GI) tract to form a colloidal mixture that softens and increases the bulk of the stool. The increased bulk stimulates peristalsis, which increases bowel motility and decreases GI transit time. These actions of methycellulose result in easy passage of stool in patients with chronic constipation. Also, due to methycellulose's ability to absorb water, it is effective in patients with chronic watery diarrhea by increasing the bulk and consistency of the stool and in patients with ileostomies or colostomies by decreasing the effluent from the stoma. Following use over several months, methylcellulose acts to decrease the rectosigmoid pressure in patients with diverticular disease or irritable bowel syndrome. This helps to relieve symptoms, such as constipation and/or diarrhea, associated with the condition.
Pharmacokinetics:
Methylcellulose is administered orally. Methylcellulose is not metabolized and is excreted in the feces.
-Route-Specific Pharmacokinetics
Oral Route
Methylcellulose is not absorbed into the circulation following oral administration. The drug distributes locally throughout the intestine, and the laxative effects are usually observed within 12-24 hours, although they may not be apparent for up to 72 hours.