What causes travel / motion sickness?
The inner ear contains the vestibular system, which comprises fluid filled canals that detect motion or changes in the body’s position and send information to the brain to be interpreted. This process helps maintain balance.
Motion sickness is thought to have originated as a defence mechanism against toxins. It is caused by conflicting information being received by the brain from the eyes and from the vestibular system. The messages sent by the ear suggest motion, whereas the messages sent by the eye suggest that the body is still and this conflict causes the brain to interpret that a neurotoxin is responsible for this “hallucination” and induces the vomiting reflex to clear the toxin from the system. Symptoms of motion sickness include nausea, vomiting and vertigo (sense of loss of balance and dizziness).
Medications for travel sickness
Medications are available that block the transmission of nerve impulses from the inner ear to the vomiting center in the brain, which blocks the vomiting reflux so preventing symptoms. A Skin patch is available containing the antiemetic anticholinergic scopolamine that works by binding to and blocking acetylcholine receptors in the vestibular system of the inner ear and in the central nervous system.