Loperamide

Administration

• Type:
• Dosage Forms:
• Routes of Administration:
• Common Trade Names: Imodium

Adult Dosing

• Acute Diarrhea:
  • 2 mg PO per dose
    • Start: 4 mg PO x1, then 2 mg PO after each loose stool; Max: 16 mg/day

• Chronic Diarrhea
  • 4-8 mg/day PO divided qd-tid
    • Start: 4 mg PO x1, then 2 mg PO after each loose stool until maint. dose established; Max: 16 mg/day

Pediatric Dosing

• Acute diarrhea:
  • 2-5 yo, 13-20 kg
    • Dose: 1 mg PO x1 after each loose stool
      • Max: 3 mg/day
      • Use OTC 1 mg/5 sol or 1 mg/7.5 mL susp
  • 6-8 yo, 20-30 kg
    • Dose: start 2 mg PO x1, then 1 mg PO after each loose stool
      • Max: 4 mg/day
  • 8-11 yo, 30-40 kg
    • Dose: start 2 mg PO x1, then 1 mg PO after each loose stool
      • Max: 6 mg/day
  • 12 yo and older
    • Dose: start 4 mg PO x1, then 2 mg PO after each loose stool
      • Max: 8 mg/day
• Chronic diarrhea
  • 0.08-0.24 mg/kg/day PO divided bid-tid
    • Max: 2 mg/dose

Special Populations

• Pregnancy Rating: B
• Lactation risk: Probably safe

Renal Dosing

• Adult:

Hepatic Dosing

• Adult/Pediatric: Reduced first-pass metabolism
  • CNS toxicity

Contraindications

• Allergy to class/drug

Adverse Reactions

Serious

• toxic megacolon
• paralytic ileus
• angioedema
• anaphylaxis/anaphylactoid rxn
• toxic epidermal necrolysis
• Stevens-Johnson syndrome
• erythema multiforme
• urinary retention
• heat stroke

Common

• constipation
• nausea
• abdominal cramps
• dizziness

Pharmacology

• Half-life: Half-life: 10.8h
• Metabolism: liver; CYP450: 2C8, 3A4 substrate; Info: P-gp substrate; 40% systemic absorption
• Excretion: feces 30%, urine <2%

Mechanism of Action

binds gut wall opioid receptor, inhibiting peristalsis; increases anal sphinctor tone

References

• Epocrates: Loperamide