What is the recommended treatment for diarrhea?

Treatment of Diarrhea

For adults with acute uncomplicated watery diarrhea, oral rehydration with reduced osmolarity ORS is the cornerstone of treatment, combined with early resumption of normal diet; loperamide (2-4 mg initially, then 2 mg after each loose stool, maximum 16 mg/day) can be added in immunocompetent adults to reduce symptom severity and duration, but antimicrobials are generally not indicated unless there is high fever, bloody stools, or recent international travel. 1, 2

Initial Assessment and Risk Stratification

First, determine if this is complicated or uncomplicated diarrhea by checking for warning signs:

• Bloody or tarry stools (melena) 3
• High fever (>38.5°C) 1
• Signs of severe dehydration (altered mental status, poor perfusion, tachycardia) 1
• Immunocompromised status 1, 2
• Age <2 years or >75 years 1, 4
• Severe vomiting preventing oral intake 1

If any warning signs are present, this requires urgent medical evaluation and hospitalization. 3, 2

Fluid Replacement: The Foundation of Treatment

For Mild to Moderate Dehydration

Reduced osmolarity oral rehydration solution (ORS) is first-line therapy for all age groups with mild-to-moderate dehydration. 1, 2 This is more effective than simple glucose-containing drinks or sports beverages. 5

• Administer ORS at 50-100 mL/kg over 3-4 hours to replace deficit 1
• For ongoing losses, give 10 mL/kg after each loose stool 1
• Plain water should also be offered between ORS doses 1
• Nasogastric ORS administration (15 mL/kg/hour) can be used if the patient cannot drink but is not in shock 1, 2

For Severe Dehydration

Isotonic intravenous fluids (0.9% normal saline or lactated Ringer's) must be given immediately for severe dehydration, shock, or altered mental status. 1, 2

• Initial bolus: 20-60 mL/kg over 2-4 hours until pulse, perfusion, and mental status normalize 1
• Target urine output >0.5 mL/kg/hour 1
• Once stabilized, transition to ORS for remaining deficit replacement 1, 2, 6

Dietary Management

Resume age-appropriate normal diet immediately after rehydration is complete or during the rehydration process. 1, 2 There is no benefit to fasting or "resting the bowel." 1

• Continue breastfeeding throughout the illness in infants 1, 2
• Offer small, frequent, energy-rich meals 1
• Avoid spicy foods, caffeine, alcohol, and high-fat foods 1
• Temporary lactose avoidance (except yogurt and firm cheese) may reduce symptom duration 1

Antimotility Agents

Loperamide Use in Adults

Loperamide can be given to immunocompetent adults with acute watery diarrhea to reduce symptom severity and duration. 1, 7

Dosing:

• Initial dose: 4 mg 1
• Then 2 mg after each unformed stool or every 2-4 hours 1
• Maximum 16 mg/day 1, 4

Critical Contraindications for Loperamide

Never use loperamide in the following situations:

• Bloody or tarry diarrhea (risk of toxic megacolon and masking serious pathology) 3, 4
• High fever or suspected invasive bacterial infection (risk of prolonging infection) 1
• Children <18 years of age (risk of CNS depression, respiratory depression, and paralytic ileus) 1, 2, 4
• Suspected or confirmed STEC infection 1, 2
• Abdominal distention or signs of ileus 4
• Immunocompromised patients with inflammatory diarrhea 1

The FDA warns of cardiac adverse reactions including QT prolongation, torsades de pointes, and sudden death with higher-than-recommended doses, and respiratory depression and cardiac arrest in children <2 years. 4

Antimicrobial Therapy

When Antibiotics Are NOT Indicated

For most adults with acute watery diarrhea without recent international travel, empiric antimicrobials are not recommended. 1, 2 Most cases are viral and self-limiting. 8, 9

When to Consider Antibiotics

Empiric antimicrobial therapy should be considered only in:

• Febrile dysentery (fever >38.5°C with bloody stools) suggesting Shigella 1, 2
• Recent international travel with moderate-to-severe symptoms or fever 1, 7
• Suspected cholera with severe watery diarrhea and dehydration 1
• Immunocompromised patients who are ill-appearing 1, 2

First-line antibiotic choice: Azithromycin 500 mg single dose for acute watery diarrhea or 1000 mg single dose for febrile dysentery 7

Alternative: Fluoroquinolones (ciprofloxacin 750 mg or levofloxacin 500 mg single dose), though resistance is increasing, particularly for Campylobacter 1, 7

Critical: Avoid antibiotics in suspected STEC O157 or Shiga toxin 2-producing E. coli as they increase risk of hemolytic uremic syndrome. 1, 2

Special Populations

Cancer Patients on Chemotherapy

For chemotherapy-induced diarrhea:

• Grade 1-2: Loperamide as above, plus budesonide 9 mg daily if refractory 1
• Grade 3-4: Hospitalization, IV fluids, octreotide 100-150 mcg SC/IV three times daily (can titrate to 500 mcg) 1
• Avoid loperamide if bloody diarrhea is present 1

Immunotherapy-Induced Diarrhea

• Grade 1: Loperamide or racecadotril 1
• Grade 2: Add budesonide 9 mg daily; if persistent >3 days, use prednisone 0.5-1 mg/kg/day 1
• Grade 3-4: Prednisone 1-2 mg/kg/day IV; if no improvement in 3-5 days, add infliximab 5 mg/kg 1

Common Pitfalls to Avoid

• Using antimotility agents in children, bloody diarrhea, or high fever (risk of toxic megacolon and worsening outcomes) 1, 3, 2, 4
• Routine antibiotic use for uncomplicated watery diarrhea (promotes resistance without benefit) 1, 2
• Withholding food during illness (delays nutritional recovery) 1, 2
• Using only plain water or sports drinks instead of ORS (less effective for rehydration) 1, 5
• Giving antibiotics for suspected STEC (increases HUS risk) 1, 2
• Exceeding maximum loperamide dose of 16 mg/day (cardiac toxicity risk) 1, 4