What medications can alleviate diarrhea?

Medications for Alleviating Diarrhea

Loperamide is the first-line medication for alleviating acute diarrhea in adults due to its proven efficacy in reducing stool frequency and improving consistency, with a recommended initial dose of 4 mg followed by 2 mg after each loose stool (maximum 16 mg daily). 1, 2

First-Line Medications

Loperamide

• Mechanism: Opioid receptor agonist that decreases intestinal motility and increases water absorption 3
• Dosing:
  • Initial dose: 4 mg orally
  • Maintenance: 2 mg after each loose stool
  • Maximum: 16 mg per day 1, 2
• Best for: Acute watery diarrhea in adults, traveler's diarrhea, chronic diarrhea 2
• Contraindications:
  • Children under 12 years
  • Bloody diarrhea or high fever (>38.5°C)
  • Inflammatory diarrhea or suspected toxic megacolon 2

Bismuth Subsalicylate

• Mildly effective for acute diarrhea 2
• Less effective than loperamide but can be used as an alternative

Second-Line Medications

Antimotility Agents

• Diphenoxylate: Less effective than loperamide and has more central nervous system effects 4
• Codeine/Morphine: Can be used when loperamide is ineffective, but have more side effects 2

Antisecretory Agents

• Racecadotril: Reduces stool volume but not available in North America 2
• Octreotide: For severe cases, especially chemotherapy-induced diarrhea
  • Dosing: 100-150 μg subcutaneously/IV three times daily 2

Special Populations and Conditions

Irritable Bowel Syndrome with Diarrhea (IBS-D)

• Loperamide is suggested for IBS-D patients (conditional recommendation) 2
• Benefits: Improves stool consistency and abdominal pain
• Limitations: Limited effect on urgency symptoms and global improvement 2

Travelers' Diarrhea

• Loperamide can be used as monotherapy for mild cases 2
• For moderate to severe cases, combination with antibiotics (fluoroquinolones or azithromycin) is more effective 2
• Reduces duration of illness from 59 hours to approximately 27 hours when combined with antibiotics 2

Cancer Treatment-Related Diarrhea

• Loperamide: First-line treatment (4 mg initially, then 2 mg every 2-4 hours) 2
• For chemotherapy-induced diarrhea refractory to loperamide:
  • Octreotide: 100-150 μg subcutaneously/IV three times daily
  • Oral budesonide may be considered 2

Important Precautions

1. Avoid antimotility agents in:

   • Children under 12 years
   • Bloody diarrhea or high fever
   • Suspected bacterial enterocolitis or C. difficile infection 2

2. Seek medical attention if:

   • No improvement after 48 hours
   • Symptoms worsen
   • Warning signs develop (severe vomiting, dehydration, persistent fever, blood in stool) 2

3. Fluid replacement:

   • Maintain adequate fluid intake guided by thirst
   • Consider drinks containing glucose and electrolytes 2

Effectiveness Comparison

• Loperamide is more effective than diphenoxylate and bismuth subsalicylate preparations 5
• When combined with antibiotics for travelers' diarrhea, loperamide reduces duration of illness to less than half a day compared to approximately 1.5 days with antibiotics alone 2
• Loperamide has minimal central nervous system effects due to low oral absorption and inability to cross the blood-brain barrier 3

For most cases of acute diarrhea in adults, loperamide provides the best balance of efficacy, safety, and accessibility as an over-the-counter medication, making it the first choice for symptomatic treatment.