Traveler's diarrhea (TD) is a common illness affecting millions of people visiting developing regions. While often self-limiting, it can disrupt travel plans and cause significant discomfort. Though many cases resolve on their own with supportive care, moderate to severe cases often require antibiotics to shorten the illness duration. The best antibiotic is determined by the characteristics of the diarrhea and the geographic location of travel, as resistance patterns vary globally.
Understanding the Primary Antibiotics for TD
Several antibiotics are used to treat TD, but the increasing prevalence of antimicrobial resistance, particularly to older, formerly standard treatments, has shifted recommendations. Here are the most commonly prescribed options:
Azithromycin
Azithromycin, a macrolide antibiotic, is a preferred treatment for severe traveler's diarrhea and especially for cases involving dysentery (bloody diarrhea with fever). It is also the recommended first-line therapy for children and pregnant women. It is particularly useful for travelers returning from Southeast Asia, where fluoroquinolone resistance is high. Treatment duration and dose will vary.
Rifaximin
Rifaximin is a non-absorbed antibiotic, meaning it stays in the gastrointestinal tract and is not absorbed into the bloodstream. It is approved to treat TD caused by non-invasive E. coli. Because it does not treat invasive pathogens, it is not recommended for cases with fever or bloody stools. Rifaximin is suitable for treating moderate, non-invasive diarrhea. A typical treatment course lasts for a few days.
Fluoroquinolones
Historically, fluoroquinolones like ciprofloxacin and levofloxacin were the first-line treatment for TD. However, their use is now limited due to widespread and increasing resistance, particularly in Campylobacter and Shigella species, especially in regions like South and Southeast Asia. Fluoroquinolones also carry a black box warning from the FDA regarding serious adverse effects, including tendon rupture and mental health side effects. They may still be used in areas with low resistance, but their overall utility has diminished.
A Comparison of Traveler's Diarrhea Antibiotics
| Feature | Azithromycin | Rifaximin | Fluoroquinolones (e.g., Ciprofloxacin) |
|---|---|---|---|
| Recommended for | Severe TD, dysentery, febrile diarrhea, children, pregnant women. | Moderate, non-invasive TD caused by E. coli. | Severe, non-dysenteric TD in low-resistance areas. |
| Mechanism | Macrolide antibiotic that inhibits bacterial protein synthesis. | Non-absorbed antibiotic that stays in the gut. | Broad-spectrum antibiotics that inhibit bacterial DNA replication. |
| Effective against | Broad range of enteric bacteria, including Campylobacter and Shigella. | Non-invasive E. coli. | Broad range of bacteria, but resistance is a major issue. |
| Considerations | Risk of increased post-treatment nausea with some regimens. | Ineffective for invasive infections (fever, bloody stool). | High risk of resistance, especially in Asia; FDA black box warning. |
When and How to Use Antibiotics for TD
Medical guidelines recommend basing antibiotic use on the severity of the illness:
- Mild Diarrhea: Characterized by tolerable symptoms that do not interfere with activities. In these cases, antibiotics are not recommended. Supportive therapy with increased fluid intake and anti-motility agents like loperamide is usually sufficient.
- Moderate Diarrhea: Symptoms are distressing and interfere with planned activities. Antibiotics may be used, often combined with loperamide for faster relief. For moderate, non-invasive diarrhea, rifaximin is an option.
- Severe Diarrhea: Incapacitating symptoms, including any instance of dysentery (bloody stools) or fever. Antibiotic treatment is advised. Azithromycin is the preferred choice, especially if dysentery is present.
Antibiotic regimens for self-treatment are typically short and can significantly shorten the duration of the illness. It is crucial to have a prescription for a standby antibiotic from a healthcare provider before traveling, based on the destination's resistance patterns.
Managing Side Effects and Resistance
Using antibiotics, even for short periods, can alter the gut microbiota and contribute to the global rise of antibiotic-resistant bacteria. Travelers should practice responsible antibiotic use to mitigate these effects. Always complete the prescribed course, and if symptoms persist or worsen, particularly with fever or bloody stool, seek medical attention. The combination of antibiotics with an anti-motility agent like loperamide is well-established for safety and faster symptom resolution, except in cases of bloody diarrhea or fever.
Supportive Care and Hydration
Regardless of antibiotic use, rehydration is the most important part of treating TD, especially in children and the elderly.
- Oral Rehydration Solution (ORS): For significant fluid loss, ORS prepared with clean water is best for replacing lost fluids and electrolytes.
- Clear Fluids: For mild cases, sipping on bottled water, clear broth, or juice can help prevent dehydration.
World Health Organization information on oral rehydration therapy
Conclusion
While traveler's diarrhea is a common travel ailment, effective treatment strategies are available. The choice of what antibiotic is used for traveler diarrhea has evolved, with azithromycin and rifaximin now prominent options due to increasing fluoroquinolone resistance. Prompt and appropriate antibiotic use, when indicated for moderate to severe cases, combined with vigilant hydration, can significantly shorten the illness and prevent more serious complications. Consulting a healthcare provider before travel for an appropriate standby antibiotic based on your destination is the best course of action.
