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If this summer’s travels take you far afield, should you carry a course of Cipro in your suitcase? Here’s what you need to know about ciprofloxacin and travelers diarrhea.

Along with summer comes travel, and with travel comes traveler’s diarrhea (TD). Here is a look at ciprofloxacin, particularly as it pertains to this troublesome summertime ailment.

Traveler’s diarrhea occurs in up to 40-50% of travelers [1,2]. The risk of acquiring it depends on the travel destination, the history and immune status of the traveler, and the style of travel. Travelers to the Middle East, southern Asia, Africa, Central America, and South America have the highest risk. Individuals who stay at resorts have a lower risk of TD than backpackers or those who are more adventuresome in their sampling of the local cuisine from street vendors [1]. Patients who are on acid-suppressing medications are also at higher risk of acquiring TD, as the acidic stomach environment provides a natural mechanism for reducing infection from ingested bacteria.


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The majority of TD (50-80% of cases) is attributable to bacteria and bacterial toxins [1]. Viruses, protozoa, and helminthes make up the remaining cases. Of bacterial causes, enterotoxigenic E. coli predominate in Africa and South Asia, while other E. coli species cause the majority of cases in Latin America, and Campylobacter is top of the list in Southeast Asia. 90% of cases occur within the first two weeks of travel.

Treatment of TD:
The recommended treatment for mild cases is hydration and rest. Loperamide, which has anti-motility and anti-secretory effects, can be used for a short period of time. However it should not be used in children, and should be avoided in patients with evidence of invasive infections, such as those with bloody stools or fevers. In moderate to severe cases, antibiotics can be effective to reduce the course of the illness. Ciprofloxacin is a first-line agent. Campylobacter in Southeast Asia have high rates of ciprofloxacin resistance, in which case azithromycin is an alternative [1].

How it works:
Like other fluoroquinolones, ciprofloxacin inhibits bacterial DNA gyrase and topoisomerase IV. It is bactericidal, and active against Gram positive and Gram negative bacteria.


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Notable History:
Ciprofloxacin was developed by Bayer Pharmaceuticals in 1983,3 and gained FDA approval in 1987. It contains only one additional carbon atom compared with norfloxacin, but has considerably higher potency for a number of different bacteria [3]. In 2000, ciprofloxacin was the first antimicrobial approved by the FDA for a biological attack; its indication for postexposure inhalational anthrax was used to justify stockpiling of the medication after the 2001 anthrax mailings.

Scope of use:
Antibiotic prophylaxis is not recommended for the general public, since the illness is generally mild, and its course can be shortened by treatment after symptoms have begun. However prophylaxis with ciprofloxacin is recommended in certain travelers, particularly those who will be ex-patria for a short period of time and need to maintain their health (politicians or athletes), as well as in those with chronic illnesses, underlying GI problems (such as inflammatory bowel disease), or who are immunocompromised in whom a bout of TD could pose a serious threat [5]. For prevention, a dose of 250-500mg daily for a maximum of three weeks can prevent 80-90% of TD cases [1].

Dosing and adjustments:
For TD, cipro can be given as a single dose of 500mg, or as 500mg BID for 3 days in more severe cases [4]. Treatment can reduce the duration of disease from several days to about one day. In regions of high Campylobacter prevalence, azithromycin should be used instead.

Adverse Events:
While there is some concern that treatment with a quinolone could increase the release of shiga-toxin by certain strains of E. coli and thereby increase the risk of Hemolytic Uremic Syndrome, shiga-toxin-releasing E. coli  are not a common cause of TD, so the risk is small. Treatment with any antibiotic could increase the risk of subsequent C. diff-associated diarrhea as well.


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Cost:
Twenty 500mg ciprofloxacin tablets are available on the $4-list at both Target and Walmart, making ciprofloxacin an affordable medication for most patients.

Christina Shenvi, MD, PhD is an assistant professor in the department of emergency medicine at the University of North Carolina.

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REFERENCES
1. Kollaritsch H, Paulke-Korinek M, Wiedermann U. Traveler’s diarrhea. Infect Dis Clin North Am. 2012;26(3):691-706.
2. Rendi-Wagner P, Kollaritsch H. Drug prophylaxis for travelers’ diarrhea. Clin Infect Dis. 2002;34(5):628-633.
3. Wise R, Andrews JM, Edwards LJ. In vitro activity of bay 09867, a new quinoline derivative, compared with those of other antimicrobial agents. Antimicrob Agents Chemother. 1983;23(4):559-564.
4. Hill DR, Ericsson CD, Pearson RD, et al. The practice of travel medicine: Guidelines by the infectious diseases society of america. Clin Infect Dis. 2006;43(12):1499-1539.
5. DuPont HL, Ericsson CD, Farthing MJ, et al. Expert review of the evidence base for prevention of travelers’ diarrhea. J Travel Med. 2009;16(3):149-160.
6. Meyerhoff A, Albrecht R, Meye JM, Dionne P, et al. US Food and Drug Administration Approval of Ciprofloxacin Hydrochloride for Management of Postexposure Inhalational Anthrax. Clin Infect Dis. 2004;39(3): 303-308.

ABOUT THE AUTHOR

Dr. Shenvi is an assistant professor in the department of emergency medicine at the University of North Carolina. She authors RX Pad each month in EPM.

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