Chapter 2The Pre-Travel ConsultationSelf-Treatable Conditions

I. Dale Carroll

RISK FOR TRAVELERS

All people, given sufficient stimulus, will develop motion sickness, although some groups are at higher risk:

• Children aged 2–12 years are especially susceptible, but infants and toddlers seem relatively immune.
• Women, especially when pregnant, menstruating, or on hormones, are more likely to have motion sickness.
• People who get migraine headaches are prone to motion sickness during a migraine and prone to getting a migraine while they are experiencing motion sickness.
• People who expect to be sick are likely to experience symptoms.

TREATMENT

Some providers feel that continued exposure to motions that induce motion sickness will diminish symptoms; however, most people will be reluctant to endure the symptoms and will want medication.Antihistamines are the most commonly used and available medications, although nonsedating ones appear to be the least effective. Sedation is the primary side effect of all the efficacious drugs. Pyridoxine hydrochloride (vitamin B₆) plus doxylamine succinate (an antihistamine) is prescribed under the brand name of Diclectin in Canada, and may be recommended in their separate forms by clinicians in the United States.

Some common prescription medications used by travelers may exacerbate the nausea of motion sickness (see Table 2-08). Other common medications used to treat motion sickness are scopolamine (oral and transdermal), meclizine, cyclizine, antidopaminergic drugs (such as promethazine), metoclopramide, sympathomimetics, benzodiazepines, prochlorperazine, and ondansetron. When recommending any of these medications to travelers, providers should make sure that patients understand the risks and benefits, the adverse event profile of the drugs, and the potential drug interactions, because these medications often have undesirable side effects. Some travelers may need to try the medication before travel to see what effect it may have.

Medications in Children

For children aged 2–12 years, dimenhydrinate (Dramamine), 1–1.5 mg/kg per dose, or diphenhydramine, 0.5–1 mg/kg per dose up to 25 mg, can be given 1 hour before travel and every 6 hours during the trip. Because some children have paradoxical agitation with these medicines, a test dose should be given at home before departure. Scopolamine may cause dangerous adverse effects in children and should not be used; prochlorperazine and metoclopramide should be used with caution in children. Antihistamines are not approved by the Food and Drug Administration to treat motion sickness in children. Caregivers should be reminded to always ask a physician, pharmacist, or other clinician, if they have any questions about how to use or dose antihistamines in children before they administer the medication. Oversedation of young children with antihistamines can lead to life-threatening side effects.

Medications in Pregnancy

Drugs with the most safety data regarding the treatment of the nausea of pregnancy are the logical first choice. Alphabetical scoring of the safety of medications in pregnancy may not be helpful, and clinicians should review the actual safety data or call the patient’s obstetric provider for suggestions. Web-based information may be found at the websites www.Motherisk.org and www.Reprotox.org.

PREVENTIVE MEASURES FOR TRAVELERS

Nonpharmacologic interventions to treat or manage motion sickness include the following:

• Being aware of situations that tend to trigger symptoms.
• Optimizing positioning—driving a vehicle instead of riding in it, sitting in the front seat of a car or bus, sitting over the wing of an aircraft, or being in the central cabin on a ship.
• Eating before the onset of symptoms, which may hasten gastric emptying, but in some people may aggravate motion sickness.
• Drinking caffeinated beverages along with medications.
• Reducing sensory input by, for example, lying prone, looking at the horizon, or shutting eyes.
• Adding distractions—aromatherapy using mint, lavender, or ginger (oral) helps some; flavored lozenges may help, as well. They may function as placebos or, in the case of oral ginger, may hasten gastric emptying.
• Using acupressure or magnets is advocated by some to prevent or treat nausea (not specifically for motion sickness), although scientific data are lacking.

BIBLIOGRAPHY

1. Benline TA, French J, Poole E. Anti-emetic drug effects on pilot performance: granisetron vs ondansetron. Aviat Space Environ Med. 1997 Nov;68(11):998–1005.
2. Priesol AJ. Motion Sickness. Rose BD, editor. Waltham MA: UpToDate; 2008.
3. Takeda N, Morita M, Horii A, Nishiike S, Kitahara T, Uno A. Neural mechanisms of motion sickness. J Med Invest. 2001 Feb;48(1–2):44–59.