What antibiotic is recommended for traveler's diarrhea?

Antibiotic Treatment for Traveler's Diarrhea

Azithromycin is the preferred first-line antibiotic for traveler's diarrhea, particularly for severe cases and dysentery, with a single 1000 mg dose showing excellent efficacy. 1

Classification and Treatment Approach

Traveler's diarrhea can be classified by severity:

• Mild: Tolerable, doesn't interfere with planned activities

  • Treatment: Antibiotics generally not recommended 1
  • Consider loperamide alone

• Moderate: Interferes with some activities

  • Treatment: Antibiotics + loperamide
  • Loperamide: 4mg initially, then 2mg after each loose stool (max 16mg/day) 2, 1

• Severe: Completely prevents planned activities or dysentery (bloody stools)

  • Treatment: Antibiotics + loperamide (if no dysentery)

Antibiotic Selection Algorithm

First-line therapy:

• Azithromycin
  • Dosing options:
    • Single dose: 1000 mg
    • Alternative: 500 mg daily for 3 days 2, 1
  • Advantages:
    • Most effective for dysentery and febrile diarrhea 2
    • Effective against fluoroquinolone-resistant Campylobacter 2, 3
    • Highest cure rate (96% at 72 hours with single dose) 4
    • Shortest median time to last unformed stool (35 hours) 4

Alternative options:

• Fluoroquinolones (for non-dysenteric cases and regions with low resistance):

  • Levofloxacin: 500 mg single dose or daily for 3 days 2
  • Ciprofloxacin: 750 mg single dose or 500 mg daily for 3 days 2, 5
  • Caution: Increasing resistance, particularly in Southeast Asia 2, 1, 3

• Rifaximin:

  • Dosing: 200 mg three times daily for 3 days 2
  • Only for non-dysenteric, non-febrile diarrhea 2, 3
  • Do not use if invasive disease is suspected 3

Adjunctive Therapy

• Loperamide:
  • Recommended as adjunctive therapy with antibiotics 1
  • Dosing: 4 mg initially, then 2 mg after each loose stool (max 16 mg/day) 2, 1
  • Significantly improves outcomes when combined with antibiotics 1, 6
  • Can be used as monotherapy for moderate cases 2
  • Contraindicated in children under 2 years 2

Regional Considerations

• Southeast Asia and India: Use azithromycin as first-line due to high fluoroquinolone resistance among Campylobacter 2, 1, 4
• Latin America and Africa: Fluoroquinolones remain effective where ETEC predominates 7

Important Caveats

• Antibiotic resistance is increasing globally, particularly to fluoroquinolones 1, 7
• Avoid continued use of loperamide if symptoms worsen or dysentery develops 2
• Consider microbiologic testing if symptoms persist beyond 14 days or if empiric therapy fails 1
• Single-dose azithromycin may cause more post-dose nausea (14% vs. <6% with other regimens), but this is mild and self-limited 4
• Antibiotic use during travel increases risk of acquiring multidrug-resistant bacteria 1

When to Consider Further Testing

• Persistent symptoms (>1 week)
• Failure of empiric therapy
• Severe or worsening symptoms despite treatment 1

In these cases, stool testing should include culture, ova and parasite examination, and specific pathogen testing as appropriate 1.