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Loperamide Hydrochloride


Class: Antidiarrhea Agents
CAS Number: 34552-83-5
Brands: Anti-Diarrheal Formula, Imodium A-D, Imodium Advanced


Antiperistaltic antidiarrhea agent; synthetic piperidine-derivative.a d

Uses for Loperamide Hydrochloride


Control and symptomatic relief of acute nonspecific diarrhea and of chronic diarrhea associated with inflammatory bowel disease.d

Effective in controlling chronic functional (idiopathic) diarrhea and chronic diarrhea caused by bowel resection or organic lesions.a

Symptomatic treatment of mild or uncomplicated travelers’ diarrhea, including that occurring in adult travelers with HIV infection.104 106 107 Should not be used in travelers with severe diarrhea or with high fever or blood in the stools;104 106 these travelers may benefit from short-term treatment with an anti-infective (e.g., a fluoroquinolone).106 107

Slideshow: Foodborne Illness: The Guest Nobody Invited

Ineffective for prevention of travelers’ diarrhea; some antiperistaltic agents may increase incidence of travelers’ diarrhea.106

Self-medication in children and adults for symptomatic control of diarrhea, including travelers’ diarrhea.101 c

Self-medication (in fixed-combination with simethicone) in children and adults for symptomatic control of diarrhea accompanied by flatulence, bloating, pressure, cramps, and gas pain.b

Ileostomy Discharge

Reduction of discharge volume from ileostomies.d

Loperamide Hydrochloride Dosage and Administration


Oral Administration

In children 2–5 years of age, administer as oral solution using only the calibrated measuring cup provided by the manufacturer.101 b Do not administer in children <2 years of age.d

Administer appropriate fluid and electrolyte replacement as needed.b

Discontinue if symptoms of acute diarrhea persist >48 hours or worsen.104 106 b c

Do not admix or dilute oral solution with other solvents.a


Available as loperamide hydrochloride; dosage expressed in terms of the salt.b c d

Pediatric Patients

Acute Diarrhea

Children 2–12 years of age: Dosage is based on age and body weight.d The following pediatric dosages are recommended for the first day of therapy:

Initial Dosage for Children 2–12 Years of Agebcd

Age (weight)

Dosage (initial 24 hours)

2–5 years (13–20 kg)

1 mg 3 times daily

6–8 years (20–30 kg)

2 mg twice daily

8–12 years (>30 kg)

2 mg 3 times daily

On the second and subsequent days of therapy, administer 0.1 mg/kg only after each unformed stool; do not exceed dosage appropriate for weight/age for the first day.d

For self-medication (alone or combined with simethicone) of acute nonspecific diarrhea, determine dosage based on body weight if possible; otherwise use age.b c The following pediatric dosages are recommended:

Dosage for Self-Medication in Children 6–12 Years of Age101102bc

Age (weight)


<6 years (≤21.4 kg)

Do not use unless directed by a clinician

6–8 years (21.8–26.8 kg)

2 mg after first unformed stool, followed by 1 mg after each subsequent unformed stool (not to exceed 4 mg in 24 hours)

9–11 years (27.3–43.2 kg)

2 mg after first unformed stool, followed by 1 mg after each subsequent unformed stool (not to exceed 6 mg in 24 hours)

≥12 years

4 mg after first unformed stool, followed by 2 mg after each subsequent unformed stool (not to exceed 8 mg in 24 hours)

Discontinue if there is no improvement after 48 hours of therapy.b c

Chronic Diarrhea

Although a dosage of 0.08–0.24 mg/kg daily in 2 or 3 divided doses has been used in a limited number of children for management of chronic diarrhea,a therapeutic dosage for this age group not established.d


Acute Diarrhea

Initially, 4 mg, followed by 2 mg after each unformed stool, up to a maximum of 16 mg daily.107 d

For self-medication, initial dosage (alone or combined with simethicone) is also 4 mg, followed by 2 mg after each subsequent unformed stool; however, do not exceed 8 mg in a 24-hour period unless directed by a clinician.101 103

Chronic Diarrhea

Initially, 4 mg, followed by 2 mg after each unformed stool until symptoms are controlled and then reduce for maintenance as required. When optimal dosage established, may administer as single or divided doses.d

In clinical trials, average maintenance dosage was 4–8 mg daily.d

If improvement after treatment with a maximum daily dosage of 16 mg is not observed within 10 days, symptoms are unlikely to be controlled by further administration.d May continue therapy if diarrhea cannot be adequately controlled with diet or specific treatment.d

Prescribing Limits

Pediatric Patients

Acute Diarrhea

Children 2–5 years of age: Maximum 3 mg daily;d not for self-medicationunless directed by a clinician.b c

Children 6–8 years of age: Maximum 4 mg daily.b c d Self-medication should not exceed 2 days unless otherwise directed by a clinician.b c

Children 9–11 years of age: Maximum 6 mg daily.b c d Self-medication should not exceed 2 days unless otherwise directed by a clinician.b c

Children ≥12 years of age: For self-medication, maximum 8 mg daily.b c Self-medication should not exceed 2 days unless otherwise directed by a clinician.b c


Acute Diarrhea

Maximum 16 mg daily.d

For self-medication, maximum 8 mg in a 24-hour period unless otherwise directed by a clinician.b c

Chronic Diarrhea

16 mg daily in divided doses.101

Cautions for Loperamide Hydrochloride


  • Known hypersensitivity to loperamide.d

  • Conditions in which constipation must be avoided.d



Do not use in patients with acute dysentery, characterized by high fever or blood in stools.d

Fluid and Electrolyte Replacement Therapy

Fluid and electrolyte depletion may occur in patients with diarrhea; in such cases, administration of appropriate fluid and electrolytes is important.d Use of loperamide does not preclude administration of appropriate fluid and electrolyte therapy.d

Infectious Diarrhea and Pseudomembranous Colitis

Antiperistaltic agents may prolong and/or worsen diarrhea resulting from some infections (e.g., those caused by Shigella, Salmonella, toxigenic Escherichia coli) and from pseudomembranous colitis associated with broad spectrum antibiotics; do not use in these conditions.a d

Toxic Megacolon

Toxic megacolon reported with agents that inhibit intestinal motility or prolong intestinal transit time in some patients with acute ulcerative colitis or pseudomembranous colitis associated with broad spectrum antibiotics; discontinue promptly if abdominal distention, constipation, or ileus occurs.d

Sensitivity Reactions


Hypersensitivity reactions, including rash, reported.a d

General Precautions

Use of Fixed Combination

When used in fixed combination with other agents, consider the cautions, precautions, and contraindications associated with the concomitant agents.

Specific Populations


Category B.d


Not known whether loperamide is distributed into human milk.d Caution advised if used in nursing women.d

Pediatric Use

Not recommended for children <2 years of age.d Use particular caution in young children due to greater variability of response to the drug; presence of dehydration, especially in younger children, may further influence variability of response.d

Not recommended for treatment of travelers’ diarrhea in infants, children, or adolescents with HIV infection.104 106

Children may be more sensitive to CNS effects than adults.d

Hepatic Impairment

In patients with hepatic impairment, monitor closely for manifestations of CNS toxicity during therapy, since first-pass metabolism may be decreased.d

Common Adverse Effects

Abdominal pain/distention/discomfort, constipation, drowsiness, dizziness, fatigue, dry mouth, nausea, vomiting, epigastric pain.d

Interactions for Loperamide Hydrochloride

No drug interactions reported during clinical trials.d

Loperamide Hydrochloride Pharmacokinetics



Peak plasma concentrations attained about 2.5 or 4–5 hours after oral solution or capsules, respectively.a d Oral bioavailability of capsules and oral solution, as determined by AUC, is similar.100

Peak plasma concentrations of loperamide metabolites are reached 8 hours following oral administration of capsules.a


Not known whether loperamide crosses the placenta or is distributed into milk.a


Elimination Route

Excreted principally in feces.d


10.8 hours (range 9.1–14.4 hours).100





Well-closed containers at 15–30°C.d




20–25°C.b c Protect fixed-combination loperamide and simethicone caplets from light.b


  • Slows intestinal motility and affects water and electrolyte movement through the bowel.d Inhibits peristaltic activity by a direct effect on circular and longitudinal muscles of the intestinal wall.d

  • Prolongs the transit time of intestinal contents; reduces fecal volume, increases fecal viscosity and bulk density, and diminishes loss of fluid and electrolytes.a d

Advice to Patients

  • When used for self-medication, importance of reading product labeling.b c When used for self-medication in children, importance of reviewing dosage information provided by the manufacturer.b c

  • Keep out of reach of children and in a child-resistant container.b c

  • Do not use for self-medication if stool is bloody or black, or if rash or other allergic reaction to the drug has occurred previously; consult clinician before use if diarrhea is accompanied by fever, mucus is present in stools, or if patient has history of liver impairment or currently is taking antibiotics.b c

  • Importance of informing clinician if diarrhea does not improve after 2 days of therapy.b c

  • Importance of seeking medical attention if diarrhea is associated with high fever, chills, or severe cramps, or is persistant or associated with severe fluid loss.105 106 107

  • Importance of adequate hydration (with clear fluids) to help prevent dehydration caused by diarrhea.101 b c

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

  • Importance of informing clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.b c

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


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

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

Loperamide Hydrochloride


Dosage Forms


Brand Names




2 mg

Loperamide Hydrochloride Capsules

Mylan, Teva


1 mg/5 mL*

Anti-Diarrheal Formula


Imodium A-D (with alcohol 0.5% and propylene glycol)



2 mg*

Anti-Diarrheal Formula Caplets


Imodium A-D Caplets (scored)


Loperamide Hydrochloride Combinations


Dosage Forms


Brand Names




2 mg with Simethicone 125 mg

Imodium Advanced Caplets


Tablets, chewable

2 mg with Simethicone 125 mg

Imodium Advanced Chewable Tablets


Comparative Pricing

This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 02/2014. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.

Imodium A-D 2MG Tablets (MCNEIL CONSUMER): 24/$19.99 or 48/$28.98

Loperamide HCl 2MG Capsules (MYLAN): 30/$12.99 or 90/$17.97

AHFS DI Essentials. © Copyright, 2004-2015, Selected Revisions August 1, 2005. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.


Only references cited for selected revisions after 1984 are available electronically.

100. Killinger JM, Weintraub HS, Fuller BL. Human pharmacokinetics and comparative bioavailability of loperamide hydrochloride. J Clin Pharmacol. 1979; 19:211-8. [IDIS 105319] [PubMed 438356]

101. McNeil Consumer. Imodium A-D (loperamide hydrochloride) caplets and oral solution prescribing information. In: Sifton DW, ed. Physicians’ desk reference. 55th ed. Montvale, NJ: Medical Economics Company Inc; 2001:1817-8.

102. Food and Drug Administration. Loperamide marketed over-the-counter. FDA Drug Bull. 1988; 18:2.

103. Lewis JH. Summary of the 31st meeting of the Food and Drug Administration gastrointestinal drugs advisory committee. December 8-9, 1986: loperamide as an OTC antidiarrheal. Am J Gastroenterol. 1987; 82:443-4.

104. US Public Health Service (USPHS) and Infectious Diseases Society of America (IDSA) Prevention of Opportunistic Infections Working Group. 2001 USPHS/IDSA guidelines for the prevention of opportunistic infections in persons with human immunodeficiency virus. From HIV/AIDS Treatment Information Services (ATIS) website ()

105. Wolfe MS. Protection of travelers. Clin Infect Dis. 1997; 25:177-86. [IDIS 392200] [PubMed 9332506]

106. Centers for Disease Control and Prevention. Health information for international travel, 2003–2004. Atlanta, GA: US Department of Health and Human Services; 2003:184-91,226-7,233. Updates available from CDC website ().

107. Anon. Advice for travelers. Med Lett Treat Guid. 2004; 2:33-40.

a. AHFS Drug Information 2003. McEvoy, GK, ed. Loperamide Hydrochloride. Bethesda, MD: American Society of Health-System Pharmacists; 2003:2740-2.

b. McNeil Consumer. Imodium Advanced (loperamide hydrochloride and simethicone) caplets and chewable tablets prescribing information. In: [database online]. Montvale, NJ: Thomson Healthcare; 2004.

c. McNeil Consumer. Imodium A-D (loperamide hydrochloride) liquid and caplets prescribing information. In: [database online]. Montvale, NJ: Thomson Healthcare; 2004.

d. Teva Pharmaceuticals. Loperamide hydrochloride capsules prescribing information. Sellersville, PA; 1998 Jul.