What is the recommended management for a healthy adult with mild‑to‑moderate traveler’s diarrhea (≤ three unformed stools in 24 hours, no fever, no blood, and no severe abdominal pain)?

Treatment of Mild-to-Moderate Traveler's Diarrhea

For a healthy adult with mild-to-moderate traveler's diarrhea (≤3 unformed stools in 24 hours without fever, blood, or severe pain), loperamide is the treatment of choice, with antibiotics reserved for cases that fail to respond quickly or when symptoms progress. 1

Initial Management Approach

For mild cases (tolerable symptoms):

• Start with loperamide: 4 mg initial dose, then 2 mg after each loose stool, maximum 16 mg per day 1, 2
• Maintain adequate fluid intake with glucose-containing drinks or electrolyte-rich soups 2
• Oral rehydration solutions are not necessary in otherwise healthy adults who can maintain fluid intake 1
• Continue eating small, light meals as tolerated; avoid fatty, spicy foods and caffeine 2

For moderate cases (distressing but not incapacitating):

• Loperamide can be used as monotherapy for symptom relief 1, 2
• Consider adding azithromycin if symptoms are particularly distressing or if rapid resolution is needed: either single 1-gram dose OR 500 mg daily for 3 days 2
• The combination of loperamide plus azithromycin reduces illness duration to less than half a day compared to either agent alone 2

Critical Safety Considerations

Immediately discontinue loperamide and escalate to antibiotics if any of the following develop: 2

• Fever (>38.5°C)
• Blood in stool
• Severe abdominal pain
• Symptoms worsen or persist beyond 48 hours

Do not use loperamide beyond 48 hours if symptoms persist - seek medical attention instead. 2

When to Use Antibiotics

The 2017 IDSA guidelines indicate that antimotility agents like loperamide significantly reduce stool volume in traveler's diarrhea, and most studies showing effectiveness used loperamide in combination with antimicrobials in healthy adults without increased adverse events. 1 However, antibiotics are not recommended for mild traveler's diarrhea where symptoms are tolerable. 2

Azithromycin is the preferred antibiotic when treatment is indicated due to widespread fluoroquinolone resistance, particularly against Campylobacter species (>85% resistance in Southeast Asia). 2, 3 A single 1-gram dose of azithromycin achieved a 96% cure rate at 72 hours in Thailand, superior to both 3-day azithromycin (85%) and levofloxacin (71%). 3

Alternative Agents

Bismuth subsalicylate is mildly effective but less potent than loperamide for symptom relief. 1

Probiotics may be offered to reduce symptom severity and duration (weak recommendation, moderate evidence), though specific organism selection and dosing varies. 1

Rifaximin (200 mg three times daily for 3 days) is effective only for non-invasive watery diarrhea caused by E. coli and should NOT be used if fever or blood is present, as it has documented treatment failures in up to 50% of cases with invasive pathogens. 2, 4

Common Pitfalls to Avoid

• Do not use loperamide in the presence of fever, bloody stools, or severe abdominal pain - this can worsen outcomes in shigellosis, STEC infections, and C. difficile, potentially increasing risk of hemolytic uremic syndrome or toxic megacolon. 1
• Do not routinely use antibiotics for mild cases - this promotes antimicrobial resistance and increases risk of C. difficile infection. 2
• Do not assume fluoroquinolones are effective - resistance now exceeds 85% for Campylobacter in many regions, making azithromycin clearly superior. 2, 3

When to Seek Medical Care

Seek immediate medical attention if: 2

• High fever with shaking chills
• Bloody diarrhea develops
• Severe dehydration (decreased urination, dizziness, extreme thirst)
• Symptoms persist beyond 48 hours despite treatment
• Overall condition deteriorates