What are the contraindications for loperamide (Imodium)?

Loperamide Contraindications

Loperamide is contraindicated in children less than 2 years of age, patients with abdominal pain without diarrhea, acute dysentery with blood in stools and high fever, acute ulcerative colitis, bacterial enterocolitis from invasive organisms (Salmonella, Shigella, Campylobacter), and pseudomembranous colitis associated with broad-spectrum antibiotics. 1

Absolute Contraindications

• Children less than 2 years of age due to risks of respiratory depression and serious cardiac adverse reactions 1
• Known hypersensitivity to loperamide hydrochloride or any excipients 1
• Abdominal pain in the absence of diarrhea 1
• Acute dysentery characterized by blood in stools and high fever 1
• Acute ulcerative colitis 1
• Bacterial enterocolitis caused by invasive organisms including Salmonella, Shigella, and Campylobacter 1
• Pseudomembranous colitis (e.g., Clostridium difficile) associated with broad-spectrum antibiotics 1

Cardiac Considerations

• Avoid in patients taking medications that prolong QT interval, including:

  • Class 1A antiarrhythmics (e.g., quinidine, procainamide) 1
  • Class III antiarrhythmics (e.g., amiodarone, sotalol) 1
  • Certain antipsychotics (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone) 1
  • Certain antibiotics (e.g., moxifloxacin) 1
  • Any other drugs known to prolong QT interval 1

• Avoid in patients with risk factors for QT prolongation:

  • Congenital long QT syndrome 1
  • History of cardiac arrhythmias or other cardiac conditions 1
  • Elderly patients with electrolyte abnormalities 1

Gastrointestinal Considerations

• Should not be used when inhibition of peristalsis is to be avoided due to risk of ileus, megacolon, and toxic megacolon 1
• Must be discontinued promptly when constipation, abdominal distention, or ileus develop 1
• Use with caution in patients with C. difficile infection as high-dose loperamide may predispose to toxic dilatation, especially in neutropenic patients 2

Special Populations

Pediatric Patients

• Contraindicated in children under 2 years of age 1
• Use with special caution in children 2-6 years due to greater variability of response and influence of dehydration 1

Elderly Patients

• No dose adjustment required but use caution as elderly may be more susceptible to QT interval prolongation 1
• Avoid in elderly taking QT-prolonging medications or with risk factors for Torsades de Pointes 1

Immunocompromised Patients

• Use with caution in AIDS patients with infectious colitis due to isolated reports of toxic megacolon 1
• Discontinue therapy at earliest signs of abdominal distention in AIDS patients 1

Clinical Considerations

• Loperamide may be given safely in patients with diarrhea before results of microbiology tests to exclude infection are available, but monitor closely 2
• Avoid in cases of complete intestinal obstruction and severe abdominal pain, which require emergency surgical assessment 2
• Use caution in patients with dehydration, as fluid and electrolyte replacement is still necessary despite loperamide treatment 1
• Avoid doses higher than recommended due to risk of serious cardiac adverse reactions 1
• Monitor for signs of abuse potential, as high doses can be misused to achieve psychoactive effects or manage opioid withdrawal 3, 4

Relative Contraindications/Use with Caution

• Patients with fever and bloody diarrhea (dysentery) 2, 5
• Patients with inflammatory diarrhea where slowing intestinal transit may worsen condition 2
• Patients with suspected STEC (Shiga toxin-producing E. coli) infections, as antimotility agents may increase risk of hemolytic uremic syndrome 2
• Patients taking CYP3A4 inhibitors which may elevate loperamide concentrations 6, 4

Remember that loperamide should be used only for symptomatic treatment of diarrhea, and whenever an underlying etiology can be determined, specific treatment should be given when appropriate 1.