What is the recommended treatment for diarrhea?

Treatment of Diarrhea

For otherwise healthy adults with acute watery diarrhea, maintain adequate fluid intake with glucose-containing drinks or electrolyte-rich soups, and use loperamide 4 mg initially followed by 2 mg after each loose stool (maximum 16 mg/day) as the first-line antidiarrheal agent. 1

Initial Assessment and Risk Stratification

Before initiating treatment, identify patients who require immediate medical supervision rather than self-management:

• Warning signs requiring medical evaluation: High fever >38.5°C, frank blood in stools (dysentery), severe vomiting, obvious dehydration, or tarry/melena stools 1, 2
• High-risk populations: Immunocompromised patients, those with significant comorbidities, frail or elderly patients >75 years, children <12 years (some guidelines accept >6 years), and those with chronic bowel disease 1
• Contraindications to antidiarrheals: Bloody or tarry diarrhea, high fever with bloody stools, suspected inflammatory/infectious colitis, or abdominal distention 2, 3

Critical pitfall: Never administer loperamide or other antimotility agents when blood is present in stool, as this may worsen outcomes by delaying pathogen elimination and can precipitate toxic megacolon 2, 3

Rehydration Strategy

For Mild to Moderate Dehydration

Oral rehydration is the cornerstone of treatment for all forms of diarrhea:

• Reduced osmolarity oral rehydration solution (ORS) is first-line therapy for mild-moderate dehydration in all age groups 1, 4
• For otherwise healthy adults with acute diarrhea, ORS is not mandatory—glucose-containing drinks (lemonades, sweet sodas, fruit juices) or electrolyte-rich soups are sufficient 1
• Maintain fluid intake guided by thirst 1
• Nasogastric ORS administration may be considered if oral intake is not tolerated 1, 4

For Severe Dehydration

Isotonic intravenous fluids (lactated Ringer's or normal saline) are required for:

• Severe dehydration, shock, or altered mental status 1, 4
• Failure of oral rehydration therapy 1
• Presence of ileus 1

IV rehydration protocol:

• Continue IV fluids until pulse, perfusion, and mental status normalize 1, 4
• Transition to ORS for remaining deficit replacement once stabilized 1, 4
• Replace ongoing stool losses with ORS until diarrhea resolves 1, 4

Antidiarrheal Medications

Loperamide (First-Line Agent)

Dosing for adults:

• Initial dose: 4 mg, followed by 2 mg every 2-4 hours or after each unformed stool 1
• Maximum daily dose: 16 mg 1
• May be given to immunocompetent adults with acute watery diarrhea 1

Absolute contraindications:

• Children <18 years of age 1
• Bloody or inflammatory diarrhea 1, 2, 3
• High fever with suspected bacterial invasion 3
• Abdominal distention or ileus 3
• Immunocompromised patients with bloody diarrhea 2

FDA warnings: Avoid doses higher than recommended due to risk of serious cardiac adverse reactions including QT prolongation, Torsades de Pointes, and sudden death 3

Alternative Opioid Agents

For refractory cases or cancer-related diarrhea:

• Tincture of opium, morphine, or codeine may be used 1
• Low-dose morphine concentrate is more cost-effective than tincture of opium for persistent diarrhea 1

Octreotide

For severe or refractory diarrhea (particularly in cancer patients):

• Starting dose: 100-150 mcg subcutaneous/IV three times daily 1
• May titrate up to 500 mcg three times daily or 25-50 mcg/hour continuous IV infusion 1

Antimicrobial Therapy

Empiric antimicrobials are NOT recommended for most acute watery diarrhea without recent international travel 1, 4

Exceptions for Empiric Antimicrobial Use:

• Immunocompromised patients 1, 4
• Ill-appearing young infants 1, 4
• Moderate to severe traveler's diarrhea with fever and/or bloody stools 1
• Suspected shigellosis with bloody diarrhea 4
• Recent international travelers with fever ≥38.5°C or signs of sepsis 4

Antimicrobial selection:

• Quinolones (fluoroquinolones) are first-line for traveler's diarrhea and suspected bacterial dysentery 1
• Cotrimoxazole is second-line (though increasing resistance limits use) 1
• Modify or discontinue when specific pathogen identified 1, 4

Critical contraindication: Avoid antimicrobials in STEC O157 and other Shiga toxin 2-producing E. coli infections, as they may increase risk of hemolytic uremic syndrome 1, 4

Dietary Management

Resume age-appropriate diet during or immediately after rehydration 1, 4

• Consumption of solid food should be guided by appetite 1
• Small, light meals are recommended 1
• Avoid: Fatty, heavy, spicy foods, caffeine (including cola drinks), and alcohol 1
• Lactose restriction: Avoid milk and dairy products (except yogurt and firm cheeses) during chemotherapy-induced diarrhea or prolonged episodes 1
• Continue breastfeeding throughout diarrheal episodes in infants 1, 4

Important note: There is no evidence that fasting or dietary restriction hastens recovery in adults 1

Special Populations

Cancer Patients with Chemotherapy/Immunotherapy-Induced Diarrhea

Grade 1-2 diarrhea:

• Loperamide as first-line 1
• Budesonide 9 mg once daily may be added if no bloody diarrhea 1
• Oral corticosteroids (0.5-1 mg/kg/day prednisone equivalent) for diffuse ulceration, bleeding, or persistent symptoms after 3 days 1

Grade 3-4 diarrhea:

• IV corticosteroids 1-2 mg/kg/day prednisone equivalent 1
• Avoid loperamide and opioids 1
• Infliximab 5 mg/kg if symptoms persist >3-5 days 1
• Vedolizumab as alternative to infliximab 1

Radiation-Induced Diarrhea

• Bile acid sequestrants (cholestyramine, colestipol, colesevelam) for bile salt malabsorption 1

Chemotherapy-Specific Antidotes

• Uridine triacetate 10 g orally every 6 hours for 20 doses for early-onset, severe, or life-threatening 5-FU or capecitabine toxicity within 96 hours of administration 1

When to Seek Medical Evaluation

Patients should obtain medical care if:

• No improvement within 48 hours 1
• Symptoms worsen or overall condition deteriorates 1
• Development of warning signs: severe vomiting, dehydration, persistent fever, abdominal distension, or frank blood in stools 1

Key Clinical Pitfalls to Avoid

• Never use antimotility agents with bloody/tarry diarrhea—this can mask serious conditions requiring urgent intervention and may precipitate toxic megacolon 2, 3
• Do not routinely prescribe antimicrobials for acute watery diarrhea—most cases are viral and self-limited 1, 4
• Avoid withholding food during diarrheal illness—early refeeding does not prolong symptoms 1, 4
• Do not use loperamide in children <18 years—risk of serious adverse effects including respiratory depression and cardiac events 1, 3
• Never exceed maximum loperamide dose of 16 mg/day—higher doses carry risk of fatal cardiac arrhythmias 1, 3