Treatment for Diarrhea in Adults
For otherwise healthy adults with acute uncomplicated diarrhea, start loperamide 4 mg initially followed by 2 mg after each unformed stool (maximum 16 mg daily) combined with adequate fluid intake guided by thirst. 1, 2
Initial Assessment: Identify Red Flags
Before initiating treatment, determine if the patient requires immediate medical supervision by screening for warning signs 1:
- High fever >38.5°C and/or frank blood in stools (dysentery) 1
- Severe vomiting that could lead to rapid dehydration 1
- Obvious clinical dehydration (tachycardia, decreased skin turgor, oliguria) 1
- Age >75 years or frail elderly 1
- Significant systemic illness or immunosuppression 1
- Chronic bowel disease 1
If any red flags are present, hospitalize and evaluate with multidisciplinary team including gastroenterology. 1
Treatment for Uncomplicated Acute Diarrhea
Fluid Management
Maintain adequate fluid intake as indicated by thirst - this is the cornerstone of management regardless of etiology. 1, 3, 4
- Use glucose-containing drinks (lemonades, sweet sodas, fruit juices) or electrolyte-rich soups 1
- Oral rehydration solutions (ORS) are NOT needed in otherwise healthy adults with mild-moderate diarrhea, despite being essential in children 1
- For severe dehydration: administer IV fluids (lactated Ringer's or normal saline) at rates exceeding ongoing losses, targeting urine output >0.5 mL/kg/h 1, 4
Antidiarrheal Medication
Loperamide is the drug of choice for symptomatic relief 1, 2:
- Initial dose: 4 mg (two 2 mg capsules) 2
- Maintenance: 2 mg after each unformed stool 2
- Maximum: 16 mg daily (eight capsules) 2
- Clinical improvement typically occurs within 48 hours 2
Evidence supports that loperamide diminishes diarrhea and shortens duration without prolonging the disorder in adults. 1
Dietary Recommendations
Resume normal eating guided by appetite - there is no evidence that solid food hastens or retards recovery. 1
- Recommend small, light meals 1
- Avoid fatty, heavy, spicy foods and caffeine (including cola drinks) 1
- Consider avoiding milk and dairy products (except yogurt and firm cheeses), particularly if diarrhea persists beyond a few days 1, 4
Antimicrobials
Do NOT use empiric antibiotics for routine acute diarrhea in residents. 1, 4
Reserve antibiotics for:
- Traveler's diarrhea (moderate-severe, or with fever/bloody stools): quinolones are first-line, cotrimoxazole second-line 1
- Proven specific pathogens after diagnostic testing 4
When to Seek Medical Evaluation
Direct patients to seek medical advice if: 1
- No improvement within 48 hours 1
- Symptoms worsen or overall condition deteriorates 1
- Warning signs develop: severe vomiting, dehydration, persistent fever, abdominal distension, or frank blood in stools 1
Special Populations
Chronic Diarrhea (>14 days)
For diarrhea lasting 3+ weeks, diagnostic workup is warranted before continuing empiric treatment. 4
- Continue loperamide: start 4 mg, then 2 mg after each unformed stool until controlled, then reduce to maintenance dose (average 4-8 mg daily, maximum 16 mg daily) 2
- Rehydration remains cornerstone 4
- Avoid empiric antimicrobials without diagnostic testing 4
Immunotherapy-Induced Diarrhea (Cancer Patients)
Grade 1 (mild): oral rehydration plus racecadotril or loperamide 3
Grade 2 (moderate): stop immunotherapy, add budesonide 9 mg daily if no bloody diarrhea 3
Grade 3-4 (severe): AVOID all antimotility agents including loperamide; use IV corticosteroids 1-2 mg/kg/day prednisone equivalent 1, 3
Critical Pitfalls to Avoid
- Never use loperamide in suspected inflammatory diarrhea, dysentery, or with fever - risk of toxic megacolon 3
- Never exceed 16 mg loperamide daily - risk of serious cardiac adverse reactions including QT prolongation 2
- Avoid loperamide in children <2 years - contraindicated due to respiratory depression risk 2
- Do not routinely order stool cultures in mild-moderate cases without red flags 5
- Probiotics are not recommended for early treatment of acute diarrhea in adults 1