Current issues of ACP Journal Club are published in Annals of Internal Medicine


Single-dose ciprofloxacin stemmed travelers' diarrhea

ACP J Club. 1995 Mar-April;122:43. doi:10.7326/ACPJC-1995-122-2-043

Source Citation

Salam I, Katelaris P, Leigh-Smith S, Farthing MJ. Randomised trial of single-dose ciprofloxacin for travellers' diarrhoea. Lancet. 1994 Dec 3;344:1537-9.



To study the effectiveness of ciprofloxacin for acute diarrhea in travelers.


3-day randomized, double-blind, placebo-controlled trial.


5 army bases in Belize.


Within 8 weeks of arriving in Belize, 88 British marines had developed diarrhea (passage of ≥ 1 unformed stool) and were seen on the day of the first loose stool. Patients with blood in their stools, temperature > 38.5 °C, or severe dehydration were excluded. 83 patients (94%) completed the study.


Patients were allocated to a single dose of ciprofloxacin, 500 mg (n = 45), or to placebo (n = 38).

Main outcome measures

Duration (time from last liquid and last unformed stool) and severity (cumulative numbers of liquid and unformed stools) of illness. Patients recorded number and types of stools (watery, loose, soft, and normal) and presence of cramps, abdominal pain, vomiting, nausea, and anorexia.

Main results

Patients receiving ciprofloxacin had a shorter duration of diarrhea than did patients receiving placebo (mean time to last liquid stool 20.9 h vs 50.4 h and mean time to last unformed stool 24.8 h vs 53.5 h, respectively;, P < 0.001 for both comparisons). Patients receiving ciprofloxacin had half the number of liquid and unformed stools as those receiving placebo (mean number of liquid stools 5.0 vs 11.4, {95% CI for the 6.4 difference 6.0 to 6.8}* and mean number of unformed stools 5.3 vs 11.7, respectively). The groups did not differ for associated symptoms, and no adverse effects were reported.


Ciprofloxacin was effective in reducing the duration and severity of acute diarrhea in travelers.

Sources of funding: Army Medical Services and the Digestive Disease Research Centre, Medical College of St. Bartholomew's Hospital.

For article reprint: Dr. M. Farthing, Department of Gastroenterology, St. Bartholomew's Hospital, London EC1A 7BE, United Kingdom. FAX 44-171-982-6121.

*Numbers calculated from data in article.


This is a "neat" study by Salam and colleagues, well constructed and clearly stated. One 500-mg dose of ciprofloxacin administered shortly after the onset of symptoms reduces by half both the severity and duration of diarrhea in travelers and does not change the accompanying symptoms (which are undoubtedly related to the host's cytokine response). This is not a study of attack rate, a recommendation for prophylaxis, or a study of severe disease, nor does it compare the effectiveness of different drugs or establish a minimally effective dose of ciprofloxacin; the authors make no claims in these areas. Indeed, prophylaxis with several different antibiotics suggests that about 90% of cases can be avoided altogether. Universal drug prophylaxis is not recommended, however, because less than one third of travelers will develop diarrhea, which is almost always self-limited, and such drug use encourages the development of drug resistance.

Several antibiotics studied over a longer treatment period, as well as bismuth subsalicylate in large volumes, had effects in shortening the course of travelers' diarrhea similar to those reported by Salam and colleagues. Doxycycline, 100 mg twice daily (1); trimethoprim, 160 mg, with sulfamethoxazole, 800 mg twice daily (2); and oral aztreonam (3) are effective but are usually prescribed (perhaps unnecessarily) for several days. Bismuth subsalicylate must be taken in large quantities (4). The authors note that ciprofloxacin in larger or more prolonged programs was previously shown to be effective and now have convincingly shown that a single dose of ciprofloxacin administered soon after diarrhea develops is also effective. It is logical to conclude that single doses of several other antibiotics would be equally effective and that trials of these antibiotics should be done.

James L. Achord, MD
The University of MississippiJackson, Mississippi, USA


1. Sack DA, Kiminsky DC, Sack RB, et al. Prophylactic doxycycline for traveler's diarrhea. Results of a prospective double-blind study of Peace Corps volunteers in Kenya. N Engl J Med. 1978; 298:758-63.

2. Ericsson CD, DuPont HL, Mathewson JJ, et al. Treatment of traveler's diarrhea with sulfamethoxazole and trimethoprim and loperamide. JAMA. 1990;263:257-61.

3. DuPont HL, Ericsson CD, Mathewson JJ, de la Cabada FJ, Conrad DA. Oral aztreonam, a poorly absorbed yet effective therapy for bacterial diarrhea in U.S. travelers to Mexico.JAMA. 1992;267:1932-5.

4. Okhuysen PC, Ericsson CD. Travelers diarrhea. Prevention and treatment. Med Clin North Am. 1992;76:1357-73.