Motion Sickness
by Iris Reyes, M.D., FACE, Dept. of Emergency Medicine, Univ. of PA and William H. Shoff, M.D., D.T.M. & H., Dept. of Emergency Medicine, Medical Director of Passport Health at the Univ. of PA

Motion sickness is one of the most common maladies affecting the traveler. Seasoned sailors get seasick sometimes. Astronauts in space flight get space motion sickness 35-85% of the time. It can occur in any mode of travel including by sea, air, road, or space ship. Animals, particularly horses, pigs and cats have been shown to experience motion sickness during travel. The degree of motion sickness can range from mild discomfort to severe incapacitation. While it can be quite debilitating, it is usually short-lived with symptoms resolving upon termination of the inciting movement. It is estimated that approximately 80% of the normal population have experienced motion sickness.

While aging does not seem to offer immunity to motion sickness, its incidence decreases between the ages of 21 to 40 years. It is more common in children between the ages of 4 and 10 years. It occurs rarely at younger than 2 years of age. Women have consistently been found to be more susceptible to motion sickness, especially with use of oral contraceptives during pregnancy and during menstruation.

Movement of the body through the environment is processed in the brain by input from sensory systems. The cause of motion sickness is considered to be a conflict between visual and inner ear sensations. It is the inability of the brain to match these two sensations that leads to symptoms of motion sickness. Symptoms may also develop from purely visual stimuli such as flight simulators or video games. It appears that this is directly proportional to how well the stimulus mimics actual motion.

Motion sickness is particularly associated with up and down movement. For example, onboard a ship, a roll rate of every 5 seconds is likely to cause illness. Movement at higher frequencies is less likely to do so.

The cardinal symptoms of motion sickness are malaise, sweats, pallor, yawning, gasping, abdominal discomfort, eructation (belching/burping), nausea and vomiting. Rapid heart beat, feeling faint from low blood pressure, and fainting may also occur. Apathy to the surrounding environment is common. Symptoms occur with varying degrees of severity. They may wax and wane or increase in severity with continued exposure to the inciting cause.

The most commonly used drug groups used to treat motion illness are promethazine (Phenergan®) and metoclopropamide (Reglan®); anticholinergics, such as scopolamine (Transderm Scope®); and antihistamines, such as meclizine (Bonine®), (Dramamine II®, OTC), diphenhydramine (Benadryl®, OTC), dimenhydrinate (Dramamine®, OTC), and buclizine (Bucladin®). These medications vary in efficacy and are generally associated with side effects. These side effects are generally mild and include sleepiness, dizziness, dry mouth, and blurred vision. There are specific contraindications to the use of each of these medications. Therefore, physician consultation should be obtained in the setting of underlying medical illness or pregnancy. Alternative therapies are also commonly used with varied success. These include the use of ginger and acupressure.

Transderm Scope® is particularly effective because it is applied as a patch on the skin and lasts for 48 hours. It requires a prescription and comes with instructions, which should be followed very carefully. Be sure to clean and dry the skin before applying the patch and after removing the patch; wash hands immediately after handling a patch both with application and removal; should not be used in children under age 10; and read the patient instruction insert carefully regarding side effects.

Strategies to prevent or lessen motion sickness:

• Position yourself where the motion is least - front seat of the car, midship, or over the wing of the plane.
• Minimize head movement. Lie back or lie down. Support your head.
• Close your eyes if that works.
• Do not read while feeling any symptoms of motion sickness; you will only feel sicker.
• Look at the horizon.
• Consider using prevention medicine particularly if you get motion sickness frequently.
• Avoid alcohol and foods high in fat, protein, and salt.
• Eat a light meal prior to travel.
• Fix your gaze on the horizon or distant object.