Preventing Traveller’s Diarrhea – A Pharmacist’s Guide
 
 
rxPassport Pharmacy Newsletter
 
August 2015
 
 
Preventing Traveller’s Diarrhea – A Pharmacist’s Guide
 
Meet Our Patients
 
Mr. and Mrs. Smith (42 and 40 y/o) walk into your pharmacy asking about the vaccine to prevent Traveller’s Diarrhea. They’re planning on visiting Romania for 1 week. They don’t have drug insurance, and are a little worried about the cost of the vaccine.
 
The only medication Mr. and Mrs. Smith take is a daily multivitamin. They don’t have any allergies.
 
They are planning on staying at a friend’s place for most of the trip. Mrs. Smith asks you if they’ll “really need” the vaccine, or if there are any less-expensive options.
 
What would you tell her?
A Review of Traveller’s Diarrhea (TD)
 
Traveller’s diarrhea is common, affecting anywhere from 30-70% of international travellers.2 It classically presents as 3 or more unformed stools over 24 hours, plus at least one of the following symptoms:7
 
Nausea
 
Vomiting
 
Abdominal cramps or pain
 
Fever
 
Blood in the stool
 
Fortunately, TD is self-limiting and often resolves within 5 days.3 TD is largely caused by Enterotoxigenic E. Coli (ETEC) or other bacteria. Viruses and protozoan causes are rarer.8
Risk Factors for TD
 
In order to decide on whether or not the vaccine is needed, we should first figure out how likely it is that our patients will develop TD. This will depend on both the travel destination and the travellers.
 
The largest risk factor for developing TD is the location of travel:1,2,8
 

*Click to enlarge

 
The type of travel and accommodation can also affect the risk of TD.1 For example, back-packers and campers have an increased risk of TD compared to people on a business trip. Longer durations of stay also lead to a greater risk of TD.1
 
Did You Know?
 
Staying at a luxury hotel doesn’t actually decrease the risk of TD compared to regular hotels.1 The staff don’t live in the hotel, after all, and they’re the ones preparing the food!
 
Gender doesn’t affect rates of TD, but age does! Adults under 30 get TD more often compared to older adults.1,2 TD rates are also higher for patients on proton-pump inhibitors.2 PPIs likely increase TD risk by reducing acid levels, which normally protects against foreign bacteria.
 
The Role of Oral Cholera Vaccines
 
The oral cholera vaccine (Dukoral® in Canada) provides some protection from ETEC, which is the primary causative organism of TD. The vaccine is estimated to have a 25% efficacy overall against TD.5
 
While this does not offer guaranteed protection, certain groups may still be interested in the vaccine. These include immunosuppressed patients, athletes attending sporting events, or other people who cannot afford to miss a day due to illness.2
 
The ultimate decision should be made by the patient, after weighing the vaccine’s cost against its modest benefits.
 
The vaccine is associated with only minor side effects, like nausea and abdominal pain.2
 
Counselling Tips!
 
The oral cholera vaccine needs 2 doses to work, separated by at least 1 week
 
The second dose needs to be taken at least 1 week before departure
 
Immunity lasts for 3 months
 
Some previously immunized patients can use just 1 booster dose instead of 2 doses5
 
The Role of Probiotics
 
Probiotics and bovine colostrum powder (Travelan®) are not currently recommended by the Centers for Disease Control for TD.2 This is due to a lack of data from rigorous clinical trials.2,3 However, probiotics are largely considered safe, so patients can feel free to try them if they’re interested.
 
The Role of Bismuth Subsalicylate
 
Bismuth Subsalicylate (BSS) can reduce the risk of TD by ~50%, when used preventatively.1,6 It can be taken in one of two ways:
 
Take 2 x 262 mg chewable tablets 4 times a day
 
Take 30 mL of the 17.5 mg/mL suspension 4 times a day
 
 
The frequent dosing might be inconvenient for the patient. BSS can cause a blackened tongue and stool, but this does not appear to cause any lasting harm to the patient.3 It has only been studied for up to 4 weeks of use6.
 
Did You Know?
 
BSS is a “salicylate”, so use all the caution you would use with ASA. For example, it cannot be given to patients with an ASA allergy. Also, it should not be given to children recovering from viral infections (including chicken pox), as this may risk triggering Reye’s syndrome.
 
BSS doesn’t have strong evidence to support regular use in the treatment of traveller’s diarrhea, but it does not appear to cause any significant harm, so patients can try it out if they want to.1
The Role of Antibiotics
 
For most patients, prophylactic antibiotics shouldn’t be used.
 
Prophylactic antibiotics can reduce rates of TD by ~90%, but they can contribute to antibiotic resistance.1 They should be considered only for high-risk, short-term travellers who cannot afford to get sick (ex. competing athletes). If they must be taken, options include fluoroquinolones and azithromycin.
 
It is much more practical for individuals travelling to a high-risk destination to bring antibiotics with them when they travel, and only use them for treatment in case of significant sickness (ex. fever, blood in the stool, or ≥ 4 unformed stools per day).8 Some common treatment regimens include:1

 
Antibiotics are often taken with loperamide 4 mg at the onset of symptoms, with an additional 2 mg after each bowel movement. When taken together, loperamide and antibiotics are better at resolving symptoms than either agent alone.1
Keep In Mind!
 
Loperamide is meant to be used for treatment of TD symptoms, not for prevention.1 Patients should always bring some loperamide when travelling to medium or high-risk areas, especially where access to medications is limited.
Counselling Points
 
Many basic strategies can help prevent traveller’s diarrhea.
 
Good hand hygiene should be encouraged for all travellers. Hands should be washed with soap and water before preparing or eating meals, or after using the washroom. If soap and water are not available, an alcohol-based hand-sanitizer is a fine substitute.2
 
In high-risk areas, food choice goes a long way! Advise patients to avoid:1,3
 

*Click to enlarge
 
† Boiling water for 1 minute should be enough to decontaminate it, regardless of altitude.2 Water that is chemically treated with iodine or chlorine may have an odd taste. Health Canada has developed a guide on how to prepare water.4
Back to the Patient
 
Mr. and Mrs. Smith decide the vaccine isn’t worth the cost. They plan to speak to their doctor about taking antibiotics with them in case of sickness.
 
You counsel them on food and beverage selection. They purchase bismuth subsalicylate from your pharmacy, along with some loperamide tablets in case their prevention strategies don’t work. The two thank you for your help and say they will return if they have any questions.
 
 
By Ashutosh Randhawa, PharmD Student
 
With appreciation to Mike Boivin, B. Pharm.
 
In this issue
 
A Review of Traveller’s Diarrhea (TD)
 
Risk Factors for TD
 
The Role of Oral Cholera Vaccines
 
The Role of Probiotics
 
The Role of Bismuth Subsalicylate
 
The Role of Antibiotics
 
Counselling Points
 
Back to the Patient
 
References
 
Pharmacy Student Blog
 
Interactive Poll
 
Q: How comfortable would you be with counselling a patient today on preventing traveller’s diarrhea?
 
Very comfortable
 
Somewhat comfortable
 
Not comfortable
 
 
Useful Resources
 
CATMAT Statement on Traveller’s Diarrhea
 
CDC Yellow Book on Traveller’s Diarrhea
 
References
 
1. CATMAT. April 2015. “Statement on Traveller’s Diarrhea”. Retrieved from: . Accessed on July 28, 2015.
 
2. Connor, B.A. July 2015. “Travelers’ Health Yellow Book – Travelers’ Diarrhea”. View Source Accessed on July 27, 2015.
 
3. Diemert, D.J. Prevention and Self-Treatment of Traveller’s Diarrhea. Clin. Microbiol. Rev. 2006; 19(3):583-594
 
4. Health Canada. January 2008. “Drinking water in the great Canadian outdoors”. View Source . Accessed on August 7, 2015.
 
5. PHAC. November 2012. “Canadian Immunization Guide. Cholera and Enterotoxigenic Escherichia Coli (ETEC) Travellers’ Diarrhea vaccine”. View Source. Accessed on August 7, 2015.
 
6. Steffen R., et al. Prevention of traveller’s diarrhea by the tablet form of bismuth subsalicylate. Antimicrob Agents Chemother. 1986; 29(4):625-7.
 
7. Treating hyperlipidemia in severe and very severe frailty (n.d). Retrieved from: View Source Steffen, R., Van Der Linde, F., Gyr, K., and Schar, M. 1983. Epidemiology of diarrhea in travelers. JAMA. 1983; 249:1176-1180.
 
8. Wanke, C.A. 2015. Travelers’ Diarrhea: Microbiology, Epidemiology, and Prevention. In: UpToDate, Calderwood S.B. (Ed). Accessed on July 27, 2015.
 
 
 
 
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