Motion sickness is a common yet unsettling experience caused by a mismatch between the signals sent to your brain from your eyes, inner ears, and body. For instance, when reading a book in a moving car, your eyes perceive a static environment, but your inner ears detect motion. This sensory conflict confuses the brain, triggering a cascade of responses that result in classic motion sickness symptoms like nausea, vomiting, and dizziness. Travel tablets, through their pharmacological actions, help reconcile this conflict by modulating the nervous system.
The Role of the Inner Ear and the Vomiting Center
At the core of motion sickness is the vestibular system, located in your inner ear, which is responsible for your sense of balance and spatial orientation. This system works in concert with your eyes and the sensory receptors in your muscles and joints to send constant updates about your body's movement to the brain. When these updates don't align, the brain becomes confused and can activate the vomiting center, a region in the brainstem. Travel tablets work by interfering with the signals that travel to and from this vomiting center, effectively preventing its activation.
Antihistamines: The Common Over-the-Counter Choice
Many of the most popular over-the-counter travel tablets are antihistamines, but they are a specific type known as first-generation antihistamines. These include active ingredients like dimenhydrinate (found in Dramamine) and meclizine (found in Bonine and Less Drowsy Dramamine).
How Antihistamines Block Motion Sickness Signals
The anti-motion sickness effect of these drugs is due to their ability to block two key neurotransmitters in the brain: histamine and acetylcholine. The first-generation antihistamines can cross the blood-brain barrier, allowing them to act directly on the central nervous system. By blocking the receptors for histamine and acetylcholine, they effectively reduce the nerve signals being sent to the brain's vomiting center, calming the nerves associated with the inner ear. This action prevents the brain from receiving the conflicting information that would otherwise lead to nausea and vomiting. Some antihistamines, like cinnarizine (available in some countries), also help by improving blood flow to the inner ear, further stabilizing the vestibular system.
Anticholinergics: For Potent, Long-Lasting Relief
For more severe cases of motion sickness or for long journeys, a healthcare provider might prescribe an anticholinergic medication, most notably scopolamine. This is typically delivered via a transdermal patch, such as Transderm Scop.
The Action of Scopolamine Patches
Scopolamine is a powerful anticholinergic that works by blocking the neurotransmitter acetylcholine, specifically targeting the nerves connecting the inner ear and the brain's balance centers. By inhibiting these signals, scopolamine provides a strong and sustained calming effect on the nervous system. The transdermal patch delivery system is particularly effective because it releases a controlled, steady dose of the medication over a prolonged period. This eliminates the need for frequent oral dosing, which can be difficult if vomiting has already begun, and provides consistent relief for extended trips like cruises.
Choosing the Right Travel Tablet for Your Journey
Selecting the best motion sickness medication depends on your specific needs, the duration of your trip, and your tolerance for potential side effects. Always consult a pharmacist or doctor for personalized advice, especially if you have other health conditions or are taking other medications.
Comparison Table: Common Motion Sickness Medications
| Feature | Dimenhydrinate (Dramamine Original) | Meclizine (Bonine, Dramamine Less Drowsy) | Scopolamine Patch (Transderm Scop) |
|---|---|---|---|
| Mechanism | Antihistamine & Anticholinergic | Antihistamine & Anticholinergic | Anticholinergic |
| Onset of Action | 30-60 minutes | 30-60 minutes | 4+ hours |
| Duration of Effect | 4-8 hours | Up to 24 hours | Up to 72 hours (3 days) |
| Drowsiness | High likelihood | Less common but possible | Less likely than oral antihistamines |
| Accessibility | Over-the-counter (OTC) | OTC | Prescription required |
| Application | Oral tablet | Oral chewable tablet | Transdermal patch behind ear |
Side Effects and Important Precautions
Like all medications, motion sickness tablets can cause side effects. Awareness of these is crucial for safe and effective use.
- Drowsiness: First-generation antihistamines, like dimenhydrinate, are well known for causing drowsiness. This can be a significant concern for those needing to remain alert, such as drivers or pilots.
- Dry Mouth and Blurred Vision: Anticholinergic effects are responsible for side effects such as dry mouth, dry eyes, and blurred vision. These are more common with scopolamine but can occur with antihistamines as well.
- Constipation: Slowing of muscle contractions in the intestines is another anticholinergic side effect that can lead to constipation.
- Interaction with Alcohol: These medications can increase the sedative effects of alcohol and other central nervous system depressants. It is best to avoid alcohol when using motion sickness tablets.
- Special Populations: Certain medications are not suitable for children or the elderly. For example, scopolamine patches are not recommended for children under 10 due to safety concerns. Always follow instructions for usage carefully. For children, it is often recommended to first try non-pharmacological methods or consult a doctor.
Natural and Behavioral Alternatives
For those who prefer a non-pharmacological approach or want to supplement medication, several methods can help manage motion sickness.
- Ginger: Ginger has been shown in some studies to help ease nausea associated with motion sickness. It can be consumed in many forms, including ginger capsules, tea, or candies.
- Acupressure: Applying pressure to the P6 or Nei Guan acupressure point on the wrist can help relieve nausea for some people. This can be done with special wristbands or by using your thumb.
- Visual Focus: Keeping your eyes on a fixed point on the horizon can help correct the sensory mismatch by aligning visual input with your vestibular system's perception of movement.
- Seating Position: In a car, sitting in the front seat can provide a better view of the horizon. In a plane, choosing a seat over the wing near the plane's center of gravity can reduce the sensation of motion.
Conclusion
Travel tablets work by utilizing pharmacological agents, primarily antihistamines and anticholinergics, to block specific nerve signals that trigger the brain's vomiting center. This addresses the core physiological cause of motion sickness—the sensory conflict. By understanding the different types of travel tablets available, including over-the-counter options like dimenhydrinate and meclizine and prescription scopolamine patches, travelers can make informed choices based on their trip's duration and symptom severity. However, because these medications have varying side effect profiles, it is always recommended to consult a healthcare professional to determine the most appropriate option for safe and effective travel.
Visit the Centers for Disease Control and Prevention (CDC) for more information on motion sickness
