What are the recommended treatments for a patient with diarrhea?

Treatment of Diarrhea

The cornerstone of diarrhea treatment is oral rehydration with reduced osmolarity ORS, combined with early resumption of normal diet, while avoiding empiric antibiotics in most cases. 1, 2, 3

Immediate Rehydration: The Priority

Assess dehydration severity first by examining skin turgor, mucous membranes, mental status, pulse, capillary refill, and weight loss (the most reliable indicator). 2, 4 Categorize as:

• Mild (3-5% deficit): Give 50 mL/kg ORS over 2-4 hours 3, 4
• Moderate (6-9% deficit): Give 100 mL/kg ORS over 2-4 hours 3, 4
• Severe (≥10% deficit, shock): Start IV lactated Ringer's or normal saline at 20 mL/kg boluses until pulse, perfusion, and mental status normalize, then transition to ORS 1, 3, 4

Use WHO-recommended reduced osmolarity ORS (245 mmol/L total osmolarity, containing Na 90 mM, K 20 mM, Cl 80 mM, HCO₃ 30 mM, glucose 111 mM) as first-line therapy—it is safer, less painful, less costly, and equally effective as IV fluids for patients who can tolerate oral intake. 1, 3

For patients unable to drink, consider nasogastric ORS administration before resorting to IV fluids. 1, 3

Nutritional Management

Resume normal, age-appropriate diet immediately during or after rehydration—do not withhold food. 1, 2, 3 This includes:

• Starches, cereals, yogurt, fruits, and vegetables 2, 4
• Continue breastfeeding throughout the entire diarrheal episode without interruption 1, 3, 4
• Resume full-strength formula immediately (do not dilute) 4
• Avoid fatty, heavy, spicy foods and caffeine 2

Early realimentation prevents malnutrition and may reduce stool output. 3

For children 6 months to 5 years in zinc-deficient regions or with malnutrition, give oral zinc supplementation to reduce diarrhea duration. 3, 4

When to Use Loperamide (and Critical Contraindications)

Loperamide may be given ONLY to immunocompetent adults with acute watery diarrhea at 2 mg per loose bowel movement (maximum 16 mg/day), and only after adequate hydration. 1, 2, 3

Absolute contraindications (FDA warnings):

• Children <18 years of age (contraindicated due to respiratory depression and cardiac risks) 1, 4, 5
• Any patient with fever or bloody stools (risk of toxic megacolon) 1, 2, 5
• Suspected inflammatory diarrhea 1, 2
• Patients taking drugs that prolong QT interval (Class IA/III antiarrhythmics, antipsychotics, certain antibiotics) 5
• Patients with cardiac arrhythmias, congenital long QT syndrome, or electrolyte abnormalities 5

The FDA has issued warnings about cardiac arrest, Torsades de Pointes, and sudden death with loperamide, particularly at higher-than-recommended doses. 5

Antibiotic Use: When to Avoid and When to Consider

Empiric antibiotics are NOT recommended for most patients with acute watery diarrhea without recent international travel. 1, 3 This is a strong recommendation based on moderate-quality evidence.

Consider antibiotics only in specific high-risk scenarios:

• Immunocompromised patients with severe illness 1, 3
• Ill-appearing young infants 1, 3
• Bloody diarrhea with presumptive shigellosis 1
• Recent international travelers with fever ≥38.5°C or signs of sepsis 1, 3
• Clinical features of sepsis with suspected enteric fever 1

Critical exception: NEVER give antibiotics for STEC O157 or Shiga toxin 2-producing E. coli—they increase risk of hemolytic uremic syndrome. 1, 3 This is a strong recommendation based on moderate-quality evidence.

Adjunctive Therapies

Probiotics may be offered to reduce symptom severity and duration in immunocompetent patients, though evidence quality is moderate. 2, 3

Ondansetron may facilitate oral rehydration when vomiting is present, but only after adequate hydration is achieved. 2 It is not recommended for children <4 years of age. 4

Red Flags Requiring Urgent Medical Attention

Seek immediate care if: 2, 3

• No improvement within 48 hours
• High fever (>38.5°C) or bloody stools develop
• Signs of severe dehydration or shock
• Abdominal distention or severe vomiting preventing oral intake

Special Populations

For cancer patients with neutropenia and diarrhea: Avoid anticholinergic, antidiarrheal, and opioid agents as they may aggravate ileus. 1 Start broad-spectrum antibiotics covering enteric gram-negatives, gram-positives, and anaerobes (piperacillin-tazobactam or imipenem-cilastatin). 1

For elderly patients: Use caution with overhydration, especially with chronic heart or kidney failure. 1 Elderly patients are more susceptible to QT prolongation with loperamide. 5