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loperamide

A07DA03

Forms & Strengths

Capsule: 2 mg
Tablet: 2 mg
Liquid: 1 mg/5 mL

Adult Dosing

Acute diarrhea: Initial 4 mg PO, then 2 mg after each loose stool; max 16 mg/day
Chronic diarrhea: Initial 4 mg PO/day, titrated up to 16 mg/day in divided doses

Pediatric Dosing

Children 2-5 years (13-20 kg): 1 mg PO TID (consult physician)
Children 6-8 years (20-30 kg): 2 mg PO BID
Children 8-12 years (>30 kg): 2 mg PO TID
Max daily dose for pediatrics varies by weight; generally avoid in children under 2 years

Indications

Symptomatic relief of acute nonspecific diarrhea
Management of chronic diarrhea associated with inflammatory bowel disease
Reduction of volume of ileostomy discharge

Mechanism of Action

Acts on opioid receptors in the intestinal muscles to inhibit peristalsis
Prolonges transit time in the intestine
Reduces fecal volume, increases viscosity, and diminishes loss of fluids and electrolytes
Increases tone of the anal sphincter

Contraindications

Hypersensitivity to loperamide
Patients with acute dysentery characterized by blood in stools and high fever
Acute ulcerative colitis or bacterial enterocolitis caused by invasive organisms
Pseudomembranous colitis associated with broad-spectrum antibiotics
Conditions where constipation must be avoided due to risk of significant sequelae

Adverse Reactions

Constipation
Abdominal pain, distension, or discomfort
Nausea and vomiting
Dizziness, drowsiness, and fatigue
Serious: Torsades de pointes, cardiac arrest, QT prolongation (with high doses)

Drug Interactions

CYP3A4 and CYP2C8 inhibitors (e.g., ritonavir, itraconazole) increase plasma concentrations
P-glycoprotein inhibitors (e.g., quinidine, ritonavir) increase central nervous system penetration
CNS depressants may enhance sedative effects
Avoid concurrent use with other QT-prolonging drugs

Curated Content: Needs Vetting Before Put to Clinical Use