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Advising patients about international travel
What they can do to protect their health and safety

Robert L. Bratton, MD  -  VOL 106 / NO 1 / JULY 1999 / POSTGRADUATE MEDICINE
Dr Bratton is consultant, department of family medicine, Mayo Clinic Jacksonville, Jacksonville, Florida.
E-mail: bratton.robert@mayo.edu.

See also Travel Med (2)

As primary care physicians, many of us are asked by our patients to make recommendations about issues affecting travel. It is our responsibility to educate them about travel-related health issues, determine their risk for disease exposure, and prescribe medications and administer immunizations to protect them from harmful organisms and diseases.

Pretrip preparation

All travelers should be encouraged to plan their trips well in advance and use experienced, respected travel agencies to make their reservations. Before departure, all reservations should be confirmed, and a copy of their itinerary should be left with family members or friends. Additional information about the weather, local tours and restaurants, and the amount of activity involved with tours should be provided by the travel agent.

Persons traveling abroad should obtain a passport 6 months before departure and visit their physician at least 1 month before the trip. They should also review their health insurance policy. If provisions for foreign travel are not included, an inexpensive short-term policy may be obtained. Patients with complicated medical conditions should be encouraged to purchase medical evacuation insurance.

All travelers with health-related problems should carry written information from their physician about their medical history (including a copy of a recent electrocardiogram, if available) and their current medications. Medical identification bracelets are also recommended.* Patients who must travel with inhalers (which may look like explosive devices) or controlled substances are advised to obtain a letter from their physician in case of customs or security questions.        
*Available from Medic Alert Foundation, 800-432-5378.

Travelers should review the specific immunization requirements for their destination. Most countries require yellow fever vaccination before entry, and immunizations for tetanus, measles, rubella, hepatitis B, influenza, and pneumococcal disease may be recommended for healthy adults. Depending on their destination and intended length of stay, serum immune globulin injections (Gamastan, Gammar) as well as immunizations for hepatitis A, cholera, meningococcal disease, typhoid fever, polio, rabies, and Japanese encephalitis may be recommended.

Specific guidelines for required and recommended vaccines are available in two publications from the Centers for Disease Control and Prevention (CDC)*: Health Information for International Travel ("The Yellow Book") and "Summary of Health Information for International Travel" ("The Blue Sheet"), which is updated weekly. Another publication, "The Green Sheet," provides up-to-date sanitation inspection reports for cruise ships. Current advice is also available from the CDC's automated International Traveler's Voice Information Service (404-332-4559). In addition, numerous online sites provide travel alerts and advice to travelers (see box below). Guidelines for international travel also may be obtained from local health departments.     
*US Government Printing Office, Washington, DC 20402; 202-512-1800.

Medications and prescriptions
All international travelers who take medication for chronic conditions should carry at least two supplies of their required drugs: one supply in a carry-on bag and the other in checked luggage. All travelers who wear eyeglasses or contact lenses should take a backup pair of glasses.

Many physicians advise their patients to travel with a supply of a general antibiotic (eg, amoxicillin, erythromycin), especially if they are going to remote areas. Other suggested medications include ciprofloxacin (Cipro), norfloxacin (Noroxin), and trimethoprim-sulfamethoxazole (Bactrim, Septra) for treating urinary infections or traveler's diarrhea. Antibiotic prophylaxis against traveler's diarrhea is not recommended . However, several placebo-controlled studies have shown that prophylactic use of bismuth subsalicylate (2 oz or two tablets four times daily) decreases the incidence of diarrhea by about 60% .

Travelers also may want to pack a supply of loperamide hydrochloride, an analgesic and antipyretic drug, an anti-inflammatory agent, an antihistamine, and an antifungal cream. Prednisone is recommended for persons with chronic obstructive pulmonary disease or asthma. In addition, a mild hypnotic agent (eg, zolpidem tartrate [Ambien]) can be helpful for adjusting to new sleep schedules. The need for other medications, such as prophylactic drugs for malaria and altitude sickness, should be determined on the basis of the traveler's destination. While traveling, patients are advised to avoid any antibiotics and nonprescription medications that they have not taken previously.

Risks posed by air travel

On flights longer than 6 hours, the risk of deep venous thrombosis and peripheral edema is increased. Therefore, passengers should be encouraged to walk and stretch during the flight. Cabin pressure in most aircraft is maintained at a level equivalent to that at altitudes of 8,000 ft or lower, which results in a decrease of PaO2 to about 60 mm Hg in healthy persons.

Passengers with lung disease and a preflight PaO2 of less than 70 mm Hg or an oxygen saturation of less than 93% may require supplemental oxygen during the flight (3).

Patients who have had a myocardial infarction should not fly for at least 3 weeks afterwards, and use of supplemental oxygen on a flight should be considered for up to 4 months. A general rule is that patients with cardiac problems should be able to walk 100 yd and climb 12 steps before attempting a long flight (4). Other cardiovascular problems are contraindications to air travel (table 1).

Table 1. Cardiovascular contraindications to commercial airline flight
Uncomplicated myocardial infarction within 3 wk
Complicated myocardial infarction within 6 wk
Unstable angina
Congestive heart failure (severe, decompensated)
Uncontrolled hypertension
Coronary artery bypass graft within 2 wk
Cardiovascular accident within 2 wk
Uncontrolled ventricular or supraventricular tachycardia
Eisenmenger's syndrome
Severe, symptomatic valvular heart disease

Adapted, with permission, from Aerospace Med. Association, Air Transport Med. Committee (1).

Persons with mobility impairments should contact the airline before the flight to arrange for assistance. In addition, those requiring special diets may wish to pack snacks or contact the airline to request special meals. Travel-related sinus and ear problems may be prevented with use of an oral or nasal decongestant 30 to 40 minutes before departure time. Some returning travelers may require treatment for barotrauma (table 2) (5).
Table 2. Treatment for ear or sinus barotrauma
Prescribe nasal decongestants:
Pseudoephedrine tablets, 60 mg q8h
Oxymetazoline HCl spray or drops
Xylometazoline HCl spray or drops
Eucalyptus or mentholin inhalant capsules

Consider antibiotic therapy if infection develops or as prophylaxis for sinus barotrauma Treat for allergic rhinitis if present
Instruct patient in Valsalva's and Frenzel maneuvers
Refer to specialist for tympanotomy, ventilation tubes, or nasal surgery if symptoms persist or recur

Adapted, with permission, from DuPont HL, Steffen R (5).

Jet lag

Jet lag is a common problem for travelers who cross multiple time zones. Symptoms include agitation, insomnia, poor concentration, and generalized fatigue. Adjustment usually takes 1 day for each time zone crossed (eg, 5 days to adapt to crossing five time zones) (6). Before a long trip, travelers can begin the adjustment process by going to bed 1 hour earlier or later each day for every time zone to be crossed, which helps entrain new circadian rhythms. Other preventive measures include avoiding alcohol and carbonated drinks before and during a flight, minimizing dehydration by drinking six to eight 8-oz glasses of water or fruit juice daily, and allowing for a flexible, relaxing schedule after arrival at the destination.

Travelers should be encouraged to adjust to local times for eating and sleeping as soon as they arrive. A short-acting hypnotic (eg, zolpidem, 5 to 10 mg at bedtime) may help establish a new sleep schedule. Studies in travelers have shown small but inconsistent reductions in jet lag symptoms with use of melatonin (7).

Motion sickness

Motion sickness may affect travelers at any time during their trip. In most cases, symptoms can be minimized with use of dimenhydrinate (50 to 100 mg every 4 to 6 hours) or meclizine (25 mg every 6 hours) beginning at least 1 hour before motion. The transdermal scopolamine patch (Transderm-Scop) has returned to the market and is well tolerated. All of these medications have anticholinergic side effects, and they should be prescribed cautiously, especially in the elderly. Some patients have reported relief with pressure-point bands (eg, Sea Bands) worn on the wrist; however, objective evidence of benefit is lacking.

Altitude sickness

Altitude sickness primarily affects travelers who spend more than 8 hours at altitudes above 10,000 ft. Mild illness involves headache (most common symptom), nausea, generalized fatigue, and shortness of breath. More severe symptoms include vomiting, ataxia, changes in mental state, fever, and cyanosis.

Mild symptoms may be treated with over-the-counter analgesics; however, more severe cases may require hospitalization. Prophylactic use of acetazolamide (Dazamide, Diamox), 250 mg twice daily, can prevent symptoms. Common side effects include paresthesias (particularly a tingling sensation in the extremities), drowsiness, nausea, anorexia, photosensitivity, and taste alterations. Acetazolamide should be avoided in patients who are allergic to sulfa drugs. A day's stay at an intermediate altitude before going to a higher altitude also may help prevent altitude sickness.

Risks to pregnant travelers

Air travel during pregnancy is usually safe but should be done cautiously after the eighth month. Although most airlines no longer require a physician's note for travel, they do recommend that pregnant women contact their physician for travel advice. If extensive immunizations or prophylactic medications (eg, antimalarial drugs) are recommended, travel should be avoided. During the flight, pregnant passengers should walk around the cabin at least every 2 hours to help prevent deep venous thrombosis.

The greatest risk to international travelers who are pregnant is the development of a complication in an area with inadequate facilities to manage the complication. When traveling by automobile, pregnant women should wear their seat belt with the lap belt positioned under the abdomen and the shoulder strap between the breasts. There is no evidence that use of safety restraints increases risk of fetal injury. The chief cause of fetal death in motor vehicle accidents is the death of the mother (8).

Diabetic complications

Patients with diabetes mellitus who travel abroad need to closely monitor their serum glucose levels. They often experience vast changes in their diet and amount of exercise (eg, walking on tours). Although patients whose condition is stable are quite capable of extensive travel, those with newly diagnosed or poorly controlled diabetes should be stabilized before taking a trip across multiple time zones.

Before a long flight, diabetic passengers can request special meals from the airline. Travelers with type 2 diabetes who take oral hypoglycemic agents can maintain their dosing schedule without regard to time zone changes. Patients with type 1 diabetes can adjust their insulin dosing according to the direction of travel (table 3). The Diabetic Alert Card, which provides emergency information in 13 languages, can be obtained from the American Diabetes Association (see box below).

Table 3. Insulin adjustments for travel through six or more time zones
WESTBOUND (day is lengthened)
Dose schedule Day of departure 18 hr after morning dose, if blood glucose is >240 mg/dL First morning at destination
Single dose Take usual dose Take one third of usual dose followed by snack or meal Take usual dose
Two doses Take usual morning dose followed by evening dose 10-12 hr later Take one third of usual morning dose followed by snack or meal Take usual dose
EASTBOUND (day is shortened)
Dose schedule Day of departure First morning at destination 10 hr after morning dose, if blood glucose is >240 mg/dL Second day at destination
Single dose Take usual dose Take two thirds of usual dose Take remaining one third of morning dose Take usual dose
Two doses Take usual morning and evening doses Take two thirds of usual morning dose Take usual evening dose plus remaining one third of morning dose Take usual two doses

Adapted, with permission, from DuPont HL, Steffen R (5).

Insulin containers should be kept in carry-on luggage and packed between layers of clothing to protect against breakage and temperature extremes (5). Insulin keeps for at least 1 month unrefrigerated if protected from freezing and temperatures above 30°C (86°F). Ideally, however, it should be refrigerated in hot climates. An insulated thermos is commercially available.*

     *Medicool Insulin Protector, 23520 Telo Ave, No. 6, Torrance, CA 90505; 800-433-2469 (in California, 800-654-1565).

Food-borne illness

The risk of traveler's diarrhea in developing countries can be as high as 60%. Contaminated foods not adequately prepared are a common cause of intestinal infections. To help prevent such illnesses, travelers should be encouraged to thoroughly clean and cook all vegetables and meats. Food should be served hot. Peeled fruits are generally safe. However, milk and milk products (eg, cheese, ice cream) that are not pasteurized, as well as cold buffets, salads, and chilled desserts, should be avoided. Consumption of seafood, beef, pork, or sausage that is raw, undercooked, smoked, pickled, or salted can lead to trichinosis or tapeworm infection. Game fish from tropical waters also may cause ciguatera poisoning. Travelers should avoid buying food from street vendors and eating in establishments that have dirty rest rooms (2,9,10).

Unsafe drinking water

Water supplies in European and other industrialized countries are generally considered safe by US standards. However, drinking water (including ice cubes and water used for brushing teeth) in remote areas or developing countries should be avoided because of the risk of giardiasis and infection with numerous other intestinal pathogens.

Whenever water purity is questionable, travelers are advised to drink bottled water (properly sealed). If bottled water is not available, drinking water should be boiled for 5 minutes before consumption. Water can also be purified with chlorine and iodine tablets. Use of water filters is not recommended, because they do not eliminate contamination with viruses, which are too small to be extracted by the filtering process. In general, hot tea, coffee, carbonated beverages, and fresh fruit juices are considered safe (11). Beer and wine are also safe, but mixed drinks containing water or ice cubes are not. Contrary to popular belief, the alcohol in mixed drinks does not kill infectious organisms.


Travelers to tropical areas are exposed to intense sunlight and dry conditions. The major cause of sunburn is exposure to ultraviolet B radiation. To block harmful radiation, travelers are advised to use a sunscreen containing para-aminobenzoic acid with a sun protection factor of at least 15. They should also wear long-sleeved, loose (preferably cotton) clothing; a wide-brimmed hat; and lip balm for dry or cracked lips. Infants and the elderly are particularly at risk and should be protected adequately. Persons taking certain medications (eg, sulfonamides, tetracycline, doxycycline, chlorothiazide [Diurigen, Diuril], phenothiazines, furosemide [Lasix], amiodarone hydrochloride [Cordarone], psoralens, nalidixic acid [NegGram], naproxen) may have an exaggerated sunburn response (12). Sunglasses with wraparound lenses should also be worn to protect the eyes against harmful ultraviolet radiation.

Protection against insects

Many diseases affecting travelers (eg, malaria, dengue fever) are carried by mosquitoes, fleas, ticks, sand flies, and tsetse flies. Protection against these vectors includes wearing proper clothing with tight-fitting wristbands, collars, and pant cuffs. An insect repellent containing at least 33% diethyltoluamide (deet) should be applied to any exposed skin, especially between dusk and dawn. Children exposed to deet may have adverse side effects (ie, ataxia, encephalopathy, seizures, and coma). Formulas containing less than 10% deet are considered safe and effective and are recommended for children (13). In remote areas, travelers should sleep in screened enclosures or under mosquito netting.

Swimming hazards

Swimming in freshwater lakes, ponds, rivers, or streams in developing countries can lead to schistosomiasis or other serious infections. In addition, many bodies of water in developing countries may be polluted and should be avoided. Chlorinated pools and salt water are generally safe and pose minimal risk of disease. Contact with jellyfish, Portuguese man-of-war, and other marine life may result in injury and should be avoided.

Medical care away from home

From witch doctors to physicians trained in Western medicine, the spectrum of healthcare providers in foreign countries varies. The local US Embassy is a good source of information about reputable practitioners and hospitals. Other sources include travel agents, hotel concierges, and English-language newspapers. A list of English-speaking physicians is also available from the International Association for Medical Assistance to Travellers (see box below).

Travelers needing medical attention in a foreign country should avoid receiving any injections or blood transfusions unless the situation is life-threatening, because sterile conditions cannot be ensured.

Safety precautions

All travelers to foreign destinations should be aware of safety risks. Crime is rampant in many areas of the world, and travelers are often thought to be easy victims. General safety recommendations to give patients include:

  • Travel with valuables in carry-on luggage and keep them in the hotel safe, if one is available. Carry copies of your passport, travel itinerary, and airline tickets separately in case the originals are lost or stolen.
  • Do not wear expensive jewelry.
  • Carry money and credit cards in a front pocket or money belt, and wear a passport pouch tucked underneath clothing at all times.
  • Avoid displaying large sums of money when purchasing items.
  • Use traveler's checks and minimize the amount of cash in your possession. However, keep a small amount of local currency available for emergencies.
  • Dress appropriately--not to attract attention--and always travel in well-lighted areas.
  • If accused of a crime, contact the local US Embassy as quickly as possible.

The leading cause of health problems in international travelers is motor vehicle accidents (14). Therefore, travelers should research locations and review directions before embarking on unsupervised tours or trips. They should wear a seat belt at all times and exercise caution when driving or walking in countries where vehicles drive on the opposite side of the road.

A few simple precautions can help travelers protect themselves in the event of an emergency. On an airline flight, passengers should book an aisle seat next to an exit (14). Similarly, they should request a hotel room near an exit on a lower floor. Health risks to avoid in foreign countries include sexual encounters with prostitutes and casual acquaintances, tattooing, acupuncture, and dental procedures.

Posttravel testing

Persons traveling in foreign countries for less than 6 months usually require no tests upon their return unless symptoms develop. However, those returning from extended stays in developing countries may want to have a complete blood cell count to check for anemia and eosinophilia, liver enzyme tests, urinalysis, a tuberculin skin test, and stool cultures for ova and parasites. Further evaluation may be needed in travelers with known or suspected exposure to infectious disease.


As international travel becomes increasingly common, primary care physicians are often asked for advice about travel-related health issues. Having a basic knowledge of both health and safety issues is essential. Pregnant women and patients with chronic medical conditions need to be aware of factors that can compromise their health during airline flights. All travelers need to know about required and recommended immunizations; prevention and treatment of jet lag, motion sickness, altitude sickness, food-borne illness, traveler's diarrhea, and sunburn; protection from insects and swimming hazards; how to obtain medical care in foreign countries; and how to protect themselves in the event of a crime or medical emergency.


  1. Aerospace Medical Association, Air Transport Medicine Committee. Medical guidelines for air travel. Aviat Space Environ Med 1996;67(10 Suppl):B1-16
  2. Centers for Disease Control and Prevention, Bureau of Epidemiology. Health information for international travel. Washington, DC: US Dept of Health, Education, and Welfare, Public Health Service, 1994
  3. Cottrell JJ. Altitude exposures during aircraft flight: flying higher. Chest 1988;93(1):81-4
  4. Kusumi RK. Medical aspects of air travel. Am Fam Physician 1981;23(6):125-9
  5. DuPont HL, Steffen R. Textbook of travel medicine and health. Hamilton, Ont: BC Decker, 1997:323-4
  6. Wolfe MS. Advice to travelers. In: Gorbach SL, Bartlett JG, Blacklow NR, eds. Infectious diseases. Philadelphia: Saunders, 1992:408-14
  7. Lamberg L. Melatonin potentially useful but safety, efficacy remain uncertain. JAMA 1996;276(13):1011-4
  8. Cunningham FG, McDonald PC, Gant NF, et al. Williams obstetrics. 20th ed. Stamford, Conn: Appleton & Lange, 1997:241
  9. Buckley GE. Traveling healthy: a guide for counseling the international traveler. Nurse Pract 1995;20(10):38, 43-5, 48-50
  10. Szela J, Band J. Traveling healthy: a guide for physicians and their patients. Contemp Intern Med 1993;5:29-44
  11. Medical information for international travelers. (Brochure) Rochester, Minn: Mayo Foundation, 1996:2
  12. Fitzpatrick TB, Johnson RA, Polano MK, et al. Color atlas and synopsis of clinical dermatology: common and serious diseases. 2d ed. New York: McGraw-Hill, Health Professions Division, 1992:211
  13. Brown M, Hebert AA. Insect repellents: an overview. J Am Acad Dermatol 1997;36(2 Pt 1):243-9
  14. Spees DN. Health care of the international traveler. In: Taylor RB, ed. Family medicine: principles and practice. 4th ed. New York: Springer-Verlag, 1994:55

Online travel medicine resources

Centers for Disease Control and Prevention Travel Information
General travel and health information for international travelers, vaccine recommendations, travel alerts, healthcare provider information, geographic health recommendations, disease outbreaks

International Association for Medical Assistance to Travellers
Directory of international physicians, general health and travel tips, immunization recommendations, world climate charts, travel supplies

Pan American Health Organization
Country health profiles; health-related publications; public information about health and travel, food and nutrition, emerging and reemerging diseases (also available in Spanish)

Health Canada Online
Latest travel-related headlines, news releases, health warnings, general advice for travelers, current information on international disease outbreaks, immunization guidelines, information for travel medicine professionals (also available in French)

World Health Organization
Overview of travel-related diseases, safety issues, health policy, health statistics, drugs and medicines, epidemiologic information, food and nutrition, global hazards

Shoreland's Travel Health Online
General travel health concerns, preventive medications and vaccines, summary of travel illnesses, US State Department publications

Medical Advisory Services for Travellers Abroad
Visa and passport information, immunization recommendations, malaria prophylaxis, general travel guidelines, recommendations for travelers with special needs, disease descriptions

International Federation of Red Cross and Red Crescent Societies
Bulletins concerning recent disasters, disaster relief projects, information on vaccines (also available in French)

Doc's Diving Medicine Home Page
Undersea medicine-related topics, issues of diving safety for sport and professional divers