Motion Sickness

Introduction

Moving vehicles like boats, airplanes, cars and amusement park rides can all trigger motion sickness.

  • Motion sickness is thought to be caused by a conflict of messages to the brain, where the vomiting centre receives information from the eyes, the GI tract and the vestibular system in the ear.
  • Children less than 2 years old are typically resistant to motion sickness; the incidence peaks at approximately 9 years of age and then decreases throughout adulthood.

Symptoms of motion sickness include nausea and sometimes vomiting, pallor and cold sweats.



Environmental Modifications

Looking at the horizon or a distant, stationary object.

Avoidance of reading or looking at a screen while in a moving environment, as this can increase conflict between vestibular and visual cues.

Selecting seats where motion is the least.

  • In a boat, lower deck and midship cabins are recommended.
  • In a car, the front seat is recommended.
  • In a plane, a seat over the front edge of the wing is recommended.
  • If travelling by train or bus, forward facing seats are recommended.

Try to keep calm and relaxed by listening to music.



OTC Medications

Treatment of acute motion sickness is often ineffective, and therefore an emphasis should be placed on prevention.

  • Long journeys may require repeat dosing while travelling, and hence the recommended dosage interval should be emphasized.

Drugs for Motion Sickness

Medications are helpful in the prevention of motion sickness but are often sedating. The most commonly used options are

  • Hyoscine (Scopolamine) hydrobromide - Antimuscarinic agent
    • The most effective drug for the prevention of motion sickness.
    • It is NOT the same as hyoscine butylbromide, which is used to reduce intestinal motility and relieve the pain of gastrointestinal smooth muscle spasm.
    • A scopolamine 1.5 mg patch can be applied behind the ear at least 4 hours before travel to help prevent nausea and vomiting caused by motion sickness. It remains effective for up to 72 hours.
  • Older, sedative antihistamines
    • The older, sedative antihistamines also have appreciable antimuscarinic activity, which contributes towards their use as antiemetics.
    • Examples include dimenhydrinate, meclizine, cyclizine, cinnarizine, promethazine.
    • The "old antihistamine" chlorpheniramine lacks antimuscarinic activity, hence is not an antiemetic.
    • Although meclizine is longer acting and associated with less drowsiness, it is less effective than dimenhydrinate for motion sickness.
    • Oral medications must be taken 30-60 minutes prior to the needed effect.

Side effects of hyoscine hydrobromide and sedating antihistamines are mainly related to anticholinergic effects and include sedation, blurred vision, dry mouth and, in older adults, confusion and urinary retention.

  • The risk of these side effects may be increased in patients concurrently taking medications with antimuscarinic effects, such as oxybutynin, tricyclic antidepressants (TCAs), and chlorpromazine.
  • Therefore, it is crucial for pharmacists to obtain a thorough medication history from patients.

NOTE: Nonsedating antihistamines do not appear to be effective for the treatment of motion sickness.



Complementary and Alternative Treatments

Ginger has been used for many years for travel sickness.

  • Clinical trials have produced conflicting findings in travel sickness.
  • The suggested mechanism of action is blockage of 5HT3 (serotonin) receptors in the GI tract.

Acupressure bands are typically applied to both wrists prophylactically.

  • Evidence of effectiveness is equivocal, but the risk of harm is low.



Summary

Prophylactic use of motion sickness medication is generally not necessary for airplane flights, ocean trips, or long drives.

  • However, it may be considered for individuals with a history of motion sickness.



External Links

Comments

Post a Comment