When should I not take anti-diarrheal medication, such as Imodium (loperamide) or Pepto-Bismol (bismuth subsalicylate)?

From the Guidelines

You should not take anti-diarrheal medications like Imodium (loperamide) or Pepto-Bismol (bismuth subsalicylate) if you have symptoms that may indicate a bacterial infection or inflammatory bowel condition, such as bloody diarrhea, high fever, or severe abdominal pain, as these medications can worsen your condition. According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea 1, antimotility drugs like loperamide should not be given to children under 18 years of age with acute diarrhea, and should be avoided in suspected or proven cases of toxic megacolon, inflammatory diarrhea, or diarrhea with fever.

Some key points to consider when deciding not to take anti-diarrheal medication include:

• Having bloody diarrhea, high fever, or severe abdominal pain, which may indicate a bacterial infection or inflammatory bowel condition
• Being under 18 years old, as loperamide is not recommended for children with acute diarrhea 1
• Having a suspected or proven case of toxic megacolon, inflammatory diarrhea, or diarrhea with fever, as loperamide can worsen these conditions 1
• Being pregnant or breastfeeding, as it is recommended to consult a doctor before using these medications
• Having diarrhea caused by certain bacteria like E. coli, Salmonella, Shigella, or C. difficile, as anti-diarrheal medications can trap the infection in the intestines and worsen the condition.

It's also important to note that while loperamide may be given to immunocompetent adults with acute watery diarrhea 1, it's not a substitute for fluid and electrolyte therapy, and medical intervention is recommended if symptoms persist or worsen over time. The most recent guideline on the pharmacological management of irritable bowel syndrome with diarrhea suggests using loperamide in patients with IBS-D, but with a conditional recommendation and very low certainty 1. However, this guideline does not supersede the more specific recommendations for infectious diarrhea 1.

From the FDA Drug Label

CONTRAINDICATIONS Loperamide hydrochloride capsules are contraindicated in: pediatric patients less than 2 years of age due to the risks of respiratory depression and serious cardiac adverse reactions patients with a known hypersensitivity to loperamide hydrochloride or to any of the excipients. patients with abdominal pain in the absence of diarrhea. patients with acute dysentery, which is characterized by blood in stools and high fever. patients with acute ulcerative colitis. patients with bacterial enterocolitis caused by invasive organisms including Salmonella, Shigella, and Campylobacter. patients with pseudomembranous colitis (e.g., Clostridium difficle) associated with the use of broad-spectrum antibiotics.

You should not take anti-diarrheal medication, such as Imodium (loperamide), in the following situations:

• If you are a pediatric patient less than 2 years of age
• If you have a known hypersensitivity to the medication or its excipients
• If you have abdominal pain without diarrhea
• If you have acute dysentery with blood in stools and high fever
• If you have acute ulcerative colitis
• If you have bacterial enterocolitis caused by invasive organisms
• If you have pseudomembranous colitis associated with broad-spectrum antibiotic use 2

From the Research

When to Avoid Anti-Diarrheal Medication

You should not take anti-diarrheal medication in the following situations:

• If you have a high fever, as this could be a sign of a more serious infection 3
• If you have bloody stools or mucus in your stool, as this could indicate a bacterial or parasitic infection 3, 4
• If you have recently taken antibiotics, as this could lead to Clostridium difficile infection 5, 6, 4
• If you have severe diarrhea with signs of dehydration, such as excessive thirst, dark urine, or dizziness 3
• If you have a weakened immune system, as anti-diarrheal medication may worsen the condition 5, 6
• If you suspect that your diarrhea is caused by a bacterial or parasitic infection, as anti-diarrheal medication may prolong the infection 3

Specific Situations to Avoid Anti-Diarrheal Medication

You should also avoid taking anti-diarrheal medication if:

• You have inflammatory bowel disease, radiation enteritis, or intestinal ischemia, as these conditions require specific treatment 3
• You are taking certain medications that may interact with anti-diarrheal medication, such as antibiotics or laxatives 5, 6
• You have traveled to an area with high risk of infectious diarrhea, as anti-diarrheal medication may not be effective against certain pathogens 7