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Motion Sickness in Children: A Normal Response to ‘Abnormal’ Stimuli |
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| Reprinted from Medscape: From Drugs & Therapy PerspectivesTM [Drug & Ther Perspect 17(1):6-9, 2001. © 2001 Adis International Limited] DISCLAIMER: This information is intended for health care practitioners. If you are not a licensed health care practitioner, consult your licensed health care provider before implementing any of the comments or suggestions contained herein. Introduction Motion sickness is an uncomfortable condition caused by exposure to unfamiliar or unnatural motion stimuli. Situations which may provoke motion sickness include car, train, air and sea travel and amusement park rides. If nonpharmacological measures are insufficient to ameliorate motion sickness, the use of pharmacological agents is advised (see Patient care guidelines). Scopolamine and some antihistamines are available for the prevention and treatment of motion sickness in children. The clinical use of these drugs in motion sickness became an established practice before neurotransmitter circuitry and receptor subtypes were identified by modern neurochemical techniques. Therefore, the development of new anti-motion sickness agents based on recent neurochemical data seems to be a promising field. Recognised by Characteristic Symptoms Motion sickness is easily recognised. It is characterised by the sequential development of a general feeling of discomfort (including epigastric discomfort), pallor (mainly facial), cold sweating, nausea and ultimately emesis.[1] Generally, after disembarking or on cessation of the motion stimulus, motion sickness symptomatology rapidly disappears.[1] Some individuals continue to experience a certain amount of general discomfort for a few hours and a few report a transient sensation of swinging, unsteadiness and disequilibrium. Children More Susceptible Than Adults It is generally agreed that infants are highly resistant to motion sickness. Susceptibility then increases with age, peaking at around 10 to 12 years, after which it begins to decrease. Females are more susceptible than males.[1] Caused by Mismatch in Sensory Information Motion sickness is not a disease but is a normal and transient response to 'abnormal' motion stimuli or contradictory spatial sensory information.[1] Any person with normal vestibular function can succumb to motion sickness if the type of motion is provocative enough and continues for a sufficient length of time.[1] A possible explanation for the causation and pathogenesis of motion sickness is the neural mismatch and sensory rearrangement theory.[2,3] This hypothesises that symptoms and signs of motion sickness are the result of a CNS response to unnatural motion stimuli transmitted to the vestibular nuclei, the archicerebellum, and to other brainstem, autonomic and hypothalamic areas. Try Nonpharmacological Measures First... Nonpharmacological measures (see table 1) should be employed in the first instance and may be helpful in both the prevention and treatment of motion sickness.[1] All nonpharmacological measures that reduce conflicting sensory input, accelerate the process of multisensory adaptation, prevent factors that might aggravate nausea and promote psychological factors which enable the individual to cope with their condition, have been reported to ameliorate motion sickness.[4] ...But Pharmacotherapy May Be Required If nonpharmacological measures are insufficient, the use of pharmacological agents is advised.[1] In general, however, anti-motion sickness medications should not be used in children younger than 2 years. There is a lack of controlled studies of the effectiveness and safety of anti-motion sickness medications in children.[1] Clinical information on these drugs tends to be based on studies in adults. Drugs Have Vestibular Suppressant Effect All pharmacological agents that have some central or peripheral vestibular suppressant effect, acting on relevant areas before motion impulses reach the vomiting centre, will be effective in the prevention or active treatment of motion sickness.[1] Common sense dictates that nonpharmacological measures should be continued in children receiving anti-motion sickness medication. Drug Choice Depends on Child and Circumstances In addition to efficacy and safety, the choice of drug for the prevention of motion sickness will be based on the child's susceptibility, and on the type, strength and duration of the anticipated motion stimulus (see Patient care guidelines). Adverse effects, particularly sedation, should be taken into account when selecting a drug to prevent motion sickness.[1] Scopolamine Very Effective... Scopolamine (hyoscine) is the most effective drug for the prevention of motion sickness.[1,5] Scopolamine is a belladonna alkaloid, tertiary amine antimuscarinic compound. ...But Use With Caution As the drug has a short duration of action when administered orally, repeated doses may be required. This may result in variable serum concentrations and considerable adverse effects (see Differential features table).[6] A transdermal system has been developed to provide effective motion sickness prophylaxis and consistent serum concentrations over an extended period of 72 hours, with less adverse effects. However, this dosage form is not recommended for use in children younger than 10 years.[5] Children are particularly susceptible to the adverse effects of belladonna alkaloids, and scopolamine should be used with caution. In fact, scopolamine is not recommended for use in children in some countries.[1] Antihistamines the Most Widely Used Antihistamines (histamine H1 receptor blockers) are the most widely used anti-motion sickness drugs in children.[1] Cinnarizine, cyclizine, dimenhydrinate, diphenhydramine and promethazine can all be used for the prevention and treatment of motion sickness in children either alone or in combination preparations with other drugs. Meclozine and buclizine are also effective in the prevention and treatment of motion sickness but are generally not used in children. Sedation the Most Prominent Adverse Effect Antihistamines have a longer duration of action and comparatively fewer adverse effects than scopolamine.[1] The most prominent adverse effect associated with the antihistamines is sedation but this varies between the drugs in this class. Promethazine and dimenhydrinate tend to produce a more marked sedation and may be selected when a sedative action is desired. However, cinnarizine and cyclizine are usually preferred as these drugs are less sedating (see Differential features table).[1,5] The nonsedating antihistamines, such as loratidine, penetrate poorly into the CNS and do not appear to be effective against motion sickness. Different Dosage Forms Increase Flexibility For motion sickness prophylaxis, an oral dose of an antihistamine is administered prior to travelling, the timing of administration depending on the drug selected (see Differential features table). Repeat doses can be given if the length of the journey warrants it. Those drugs available in other dosage forms, such as for rectal or parenteral administration, are useful for active treatment when signs of motion sickness have already appeared. Abuse Potential There have been reports of adolescents misusing some antihistamines, including dimenhydrinate and cyclizine, to induce exhilaration, euphoria and hallucinations.[1] Stimulants Not Recommended in Children A number of sympathomimetics, particularly amphetamine and ephedrine, have been reported to have anti-motion sickness effects alone or in combination with scopolamine or promethazine.[1] These drugs can also ameliorate the central adverse effects of scopolamine and promethazine (e.g. drowsiness). However, sympathomimetics are not employed in routine clinical situations and should not be used in children. Future Possibilities A large number of medications and substances have been used or recommended for the prevention of motion sickness. Those showing promise and deserving further study include:[1]
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