In a randomized, double-blind, placebo-controlled trial, 227 US adults with acute diarrhea in Mexico received a single dose of sulfamethoxazole and trimethoprim (1600/320 mg) or 3 days of therapy with loperamide hydrochloride (4-mg loading dose, then 2 mg orally after each loose stool), sulfamethoxazole-trimethoprim (800/160 mg orally twice daily), or the combination of both. Subjects treated with the combination had the shortest average duration of diarrhea compared with the placebo group (1 hour vs 59 hours), took the least amount of loperamide after the loading dose (3.8 mg), and had the shortest duration of diarrhea associated with fecal leukocytes or blood-tinged stools (4.5 hours). A single dose of sulfamethoxazole-trimethoprim was also efficacious (28 vs 59 hours), but loperamide alone was significantly effective only when treatment failures were treated with antibiotics (33 vs 58 hours). The combination of sulfamethoxazole-trimethoprim plus loperamide can be highly recommended for the treatment of most patients with travelers diarrhea.
Ericsson CD, DuPont HL, Mathewson JJ, West MS, Johnson PC, Bitsura JAM. Treatment of Traveler's Diarrhea With Sulfamethoxazole and Trimethoprim and Loperamide. JAMA. 1990;263(2):257–261. doi:10.1001/jama.1990.03440020091039