William M Stauffer

"Stop the car, Mom, I'm going to be sick!" 

By William M. Stauffer, MD, Robert J. Konop, PharmD, Gregory   A. Plotnikoff, MD, and Deepak Kamat, MD, PhD 

 Parents often ask for help with their child's motion   sickness, a condition that has become increasingly common. Is prescribing an   antihistamine or a complementary therapy a good idea? Or is prevention the best   route? This rundown of possible strategies will help you decide.  

 Motion sickness is becoming increasingly familiar to parents and pediatricians.   This malady, which is characterized by nausea and other uncomfortable symptoms   induced by passive or perceived movement, is nothing new. In fact, the word   "nausea" derives from the Greek word "naus," which means ship, indicating that   motion sickness was recognized thousands of years ago. The increase in travel   by different modes of transportation (not just boats), the prevalence of amusement   parks with their stomach-lurching rides, and the popularity of video games have   increasingly led parents to ask: "What can you do to help my child with motion   sickness?" 

 It's not easy to answer this question because literature based on evidence-based   medicine is lackingat least with regard to children. Nonetheless, a review   of accepted strategies to prevent and treat motion sickness in infants and children   should be helpful. Although use of pharmacologic agents is most common, alternative   therapies also are available. We believe these therapies on the whole, when   used appropriately, may be preferable to drugs because of their very small risk   of side effects, if any. 

 The pathophysiology of motion sickness, described in the "

" box, is extremely complex and not well understood.   The condition is common, with 58% of children reportedly experiencing car sickness.

   Even though motion sickness is usually nothing more than a minor nuisance, it   can be incapacitating.

 Certain factors have been associated with   motion sickness: 

 Age between 4 and 10 years. Children under the age of 2 years rarely experience     motion sickness.

Female gender. Regardless of age, boys are less susceptible than girls.

Consumption of dairy products and foods high in sodium, protein, and calories.

Emotional upset, ear infections, and noxious stimuli, such as environmental     smoke, which can aggravate symptoms of motion sickness.

Oral contraceptives, which enhance motion sickness in teenage girls, who     are also more likely to experience motion sickness during a menstrual period.

Low-frequency motion, such as the swaying of a boat. This type of movement     is more likely to induce motion sickness than movement that is more vigorous.

In adults, motion sickness is well characterized as epigastric discomfort, nausea, vomiting, drowsiness, headache, and generalized discomfort. The most common presenting symptom of motion sickness in children younger than 5 years, however, is ataxia, while nausea prevails in children older than 12.

In one study of children 4 to 15 years of age in whom motion sickness was evoked, those in kindergarten had marked gait abnormalities, including falls, but only minimal symptoms related to the autonomic nervous system. The frequency and severity of sickness gradually increased during growth as autonomic symptoms became more pronounced; the gait abnormalities became less severe, however. Investigators attributed this discrepancy to the poorly developed perception of spatial orientation of younger children as well as the immaturity of their vestibular system (which relates to maintenance of equilibrium), which led to the gait abnormalities that moderated as the children matured.

 Other symptoms of motion sickness commonly seen in children are vomiting, pallor, vertigo, and cold sweats. Unfortunately, vomiting does not relieve the other symptoms of motion sickness.

The most specific targets of antimotion sickness medications are the vestibular nuclei because vestibular stimuli are critical in the generation of motion sickness. Developing drugs for motion sickness has been difficult because of the multiple neurotransmitters and stimulatory and inhibitory receptors on the vestibular nuclei. Not knowing the precise pathway of motion sickness also complicates matters. Available agents generally target dopamine and acetylcholine activity, as these neurotransmitters have been most implicated in the pathophysiology of motion sickness.

are used more frequently than any other type of drug for preventing motion sickness. Their duration of action is longer, and they are considerably safer than other drugs. These agents produce varying degrees of sedation. It is not known why antihistamines have an effect on motion sickness. It could be because they act on the histamine receptors of the vestibular nuclei, because of their nonspecific suppression of the neurons, or because of the agents' anticholinergic properties. In addition to feeling tired and having other common side effects of antihistamines (dry mouth, constipation, and blurred vision), children may have a paradoxical reaction to these drugs. Warn parents about this before starting treatment.

) contains equimolar proportions of diphenhydramine and chlorotheophylline. It is widely used for preventing motion sickness in adults and children. The most pronounced side effect of dimenhydrinate is drowsiness. It also has been implicated in impeding the diagnosis of treatable conditions associated with vomiting, such as appendicitis in children, because it suppresses vomiting.

Dimenhydrinate is available in tablet, liquid, parenteral (intramuscular [IM], intravenous [IV]), and chewable tablet forms. A rectal form is not available in the United States. The extended-release formulation should not be used in children. The dosage is 5 mg/kg/d, given in four divided doses, with a maximum dosage of 400 mg/d.

 is also commonly used for preventing motion sickness in adults and children. As with dimenhydrinate, the major side effect is drowsiness, though the agent also can cause dizziness and thickening of bronchial secretions. Diphenhydramine is available in tablet, syrup, and parenteral (IM, IV) formulations. The dose is 1 mg/kg taken every four to six hours as needed (maximum dose is 25 to 50 mg). Diphenhydramine should be taken at least 30 minutes (and preferably one to two hours) before exposure to a situation expected to induce motion sickness. 

Meclizine hydrochloride (Antivert, Bonine)

 is longer acting than other antihistamines. It has not been studied in children younger than 12 years. Children are known to be especially sensitive to anticholinergics, which are pharmacologically related to meclizine. Common side effects include drowsiness, blurred vision, and dryness of the mouth, nose, and throat. Meclizine is contraindicated for children with chronic lung diseases such as asthma. The dose for children older than 12 years is 12.5 to 25 mg orally one hour before travel with repetition of the same dose every 12 to 24 hours. 

 is the most extensively used anticholinergic agent. Scopolamine nonselectively inhibits all five muscarinic receptors. It should not be used in children younger than 12 years of age because clinical data are lacking and because these youngsters are more susceptible to belladonna alkaloids than those who are older. For children older than 12 years the dose is one patch, which contains 1.5 mg of scopolamine hydrochloride. The patch is usually applied to intact skin behind the ear and has to be replaced every 72 hours. If the agent is used for long periods of time, it may cause symptoms such as headache, nausea, and dizziness upon withdrawal. Common adverse drug reactions include dry mouth, dry skin, blurred vision, difficulty urinating, constipation, and tachycardia. 

) is a phenothiazine derivative. Its antidopaminergic activity is extremely weak, but its antimuscarinic and antihistamine activity are considerably stronger. This makes prometh- azine useful for preventing and treating motion sickness; it also is effective against other emetic stimuli. Adverse events associated with promethazine include sedation, blurred vision, lowering of the seizure threshold, and dystonic reactions. (Dystonic reactions caused by phenothiazines are treated with diphenhydramine.) Promethazine should be administered with food to decrease GI irritation. It is available in syrup, tablet, suppository, and injectable forms. The pediatric dosage is 0.5 mg/kg taken orally 30 to 60 minutes before leaving on a car trip, for example, and then every 12 hours as needed. An advantage of promethazine is that it has been used extensively, both intramuscularly and as a suppository, for treating motion sickness. Promethazine should not be used in children younger than 2 years because of a possible association with sudden infant death syndrome and sleep apnea.

) are not recommended in children because they are not effective against motion sickness in adults. In addition, prochlorperazine has been associated with a high incidence of extrapyramidal side effects in children, such as tremors, rigidity, opisthotonus, torticollis, and oculogyric crisis.

 Table 1 summarizes the drugs used to treat motion sickness in children. Table   2 describes the pathways through which various classes of drugs work. 


        Drug treatment of motion sickness 


        Pathways for drug treatment of motion sickness in children

Parents are increasingly interested in "more natural" or "less toxic" options for treating their children's motion sickness. Evidence for nonpharmaceutical therapies is most frequently found for traditional or adult uses. Few randomized controlled clinical trials of such therapies have been conducted in children. Nonetheless, we recommend considering simple and safe nonpharmaceutical options such as acupressure and ginger before using drugs, which often have at least some side effects. In addition, certain drugs, such as meclizine and scopolamine, have not been studied in or recommended for patients under the age of 12 years. 

) is the most widely recognized complementary therapy for motion sickness. Ginger root is readily available in different forms (capsule, powder, candy, or tea), and the use of ginger ale for nausea and abdominal pain is based on a traditional belief in the efficacy of ginger. (However, few ginger ale sodas commercially sold today actually contain ginger.) Ginger root has been evaluated by the German government's Commission E (comparable to the US Food and Drug Administration) and has been approved for use in prevention of travel sickness symptoms. The active ingredients in ginger are believed to be 6-gingerol and a galanolactone, but their precise mechanism of action is not well understood. Ginger root has shown mixed results as an antimotion sickness agent, but no adverse effects were reported.

 Traditional dosing for adults and children older than 12 is 1,000 mg per day (taken one hour before traveling) or 250 mg orally four times a day. This dose is reduced by half for children 6 to 12 years of age and by three quarters for children 3 to 6 years of age.

 also are recommended in lay literature available to parentsin magazines, for instance, or over the World Wide Web. These teas contain anise seed (

 or are made from a tincture containing sweet sedge (

 (Wormwood is toxic if ingested chronically.) These herbs are among the 30 plants Commission E monographs cite for treating loss of appetite, indigestion, or other dyspeptic symptoms, but they have not been tested for motion sickness. Other therapies for gastric distress noted for adults include apricot juice, carrot juice, raw pumpkin or squash seeds, crushed parsley, and peppermint tea.

 are the best-studied nonpharmaceutical   interventions for both adults and, by extrapolation, for children. Classically,   stimulation of the Neiguan (P6) meridian point on the wrists produces antiemetic   effects in patients who are awake. In adults, this point is approximately 3   cm from the distal palmar crease between the palmaris longus and flexor carpi   radialis tendons (see figure). Many studies in adults have shown positive effects   of acupressure or acupuncture antiemetic prophylaxis in perioperative settings.

   Two studies of Neiguan wrist massage of P6 using wrist bands showed mixed results.

   A single study demonstrated the effectiveness of a portable acustimulation device   in controlling seasickness.

Results of investigations in children were mixed. Two studies in children undergoing strabismus surgery have demonstrated marked reduction in postoperative vomiting with P6 or K-K9 point stimulation.

 (The Korean hand acupuncture point K-K9 is located on both hands on the palmar surface of the middle phalanx of the fourth finger. It corresponds to the Chinese P6 point, but at a different location.) A well-designed study of acupressure-acupuncture antiemetic prophylaxis in children undergoing tonsillectomy demonstrated no reduction in vomiting compared with placebo.

Recently, training in self-regulation of the autonomic nervous system was shown to be superior to promethazine.

Behavioral pediatricians frequently provide this training for a variety of other medical concerns, including asthma, headaches, and functional abdominal pain. Using specially designed and commercially available video-game technologies for biofeedback therapies, most children older than 6 years can develop significant skills in self-regulation.

 Table 3 summarizes alternative therapies for motion sickness. 

Nonpharmaceutical interventions for motion sickness, particularly behavioral interventions, are not practical for very young children, who are not old enough to follow commands and suggestions. The effectiveness of behavioral interventions will depend on the developmental stage of the child. 

Certain measures taken before or during traveling can help prevent motion sickness. Parents can help their child to do the following. 

 Eat a light meal at least three hours before leaving 

 Avoid dairy products (use juices instead) and foods high in sodium, protein,     or calories 

 Sit in the front seat of a car (but only when the child's size and age     make this a safe place) 

 Focus on a stable horizon or object while moving 

 Avoid visual stimuli (reading books, playing video games) 

 Increase ventilation or exposure to cool, fresh air 

 Lie on the back whenever possible and limit head movement by placing the     head on a stable object 

 Many children suffer motion sickness, but few antimotion sickness agents with   sufficient experience or efficacy trials are available for them for routine   use. Whenever possible, we recommend using nonpharmaceutical measures. When   a family does plan on using a drug, prescribe the agent in a test dose before   a trip to determine if the child will have a paradoxical response or other side   effect. Antihistamines, particularly dimenhydrinate and diphenhydramine, are   the best agents for children because they have few side effects, are long acting,   and have the greatest clinical experience. Promethazine can be used in children   for preventing as well as treating motion sickness. The advantage of this agent   in a child with vomiting is that it can be given intramuscularly or rectally.   In view of the data currently available and known adverse effects, scopolamine   should not be used in children younger than 12 years. 

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Articles

Parents often ask for help with their child&s motion sickness, a condition that has become increasingly common. Is prescribing an antihistamine or a complementary therapy a good idea? Or is prevention the best route?