Treatment of Diarrhea After Return from Mexico

Introduction to Treatment Guidelines

The American College of Travel Medicine recommends azithromycin as the preferred first-line antibiotic for moderate to severe diarrhea in travelers returning from Mexico, given as either a single 1-gram dose or 500 mg daily for 3 days, with loperamide as adjunctive therapy for non-bloody diarrhea 1

For mild diarrhea, loperamide monotherapy is the preferred treatment, starting with 4 mg initially, then 2 mg after each loose stool, maximum 16 mg daily, and ensuring adequate hydration with oral rehydration 1, 2
For moderate diarrhea, azithromycin is recommended, either as a 1-gram single dose or 500 mg daily for 3 days, and loperamide can be used as monotherapy or combined with antibiotics 1
For severe diarrhea, azithromycin is the preferred first-line agent, particularly for dysentery, with dosing at 1-gram single dose or 500 mg daily for 3 days, and single-dose antibiotic regimens are effective and strongly recommended 1, 2

Microbiologic testing is strongly recommended for severe or persistent symptoms, bloody diarrhea, failure of empiric antibiotic therapy, and immunocompromised patients 1, 2
Persistent diarrhea beyond 14 days may indicate protozoal infections, post-infectious irritable bowel syndrome, or unmasking of chronic inflammatory bowel disease 2

There is an increasing association between travel, antibiotic use, and acquisition of multidrug-resistant bacteria, and pretravel counseling should address this risk 1, 2
Rifaximin is an option only for non-invasive watery diarrhea, but azithromycin remains preferred given its broader spectrum and effectiveness against invasive pathogens common in Mexico 1